JPH0515787B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention is based on lower compounds of the element titanium (TiCl ₂ ,
This invention relates to the chemical vapor deposition of TiCl ₃ ), and also to lower compounds of the elements vanadium and chromium, applied as coatings at low temperatures on selected substrates. Such coatings can have a variety of uses when applied to a substrate. For example, coatings of lower titanium compounds are desirable for metalworking tools to increase the useful life of the tools. Others, such as niobium nitride coatings, are useful as superconducting materials. Depending on the intended use for applying the coating or the substrate on which the coating is applied, the temperature at which the coating can be applied may be important. Often there is a critical temperature, ie, a temperature above which the properties of the substrate change. Coating drills and mechanical tools with a lower grade compound of elemental titanium to extend the useful life of the tool.
Nitride, carbide and carbonitride of titanium metal are preferred coatings. Compounds such as titanium nitride have approximately
It can be applied as a coating by chemical vapor deposition (CVD) at temperatures above 1000°C. However, most tool steels are hardened and tempered. If temperatures above the tempering temperature are used, the tool loses its temper and must be reheated. When reheating, deformation becomes a problem and adversely affects the durability of the tool. Therefore, any coating deposition is preferably carried out at a temperature below the softening point of the tool metal so as not to adversely affect the toughness of the tool steel. Coating metal compounding tools with titanium nitride is a typical example of a coating situation where low temperature deposition of the coating is desirable. Current methods deposit titanium nitride by chemical vapor deposition by passing titanium tetrachloride, nitrogen, and hydrogen onto a substrate at temperatures above about 1000°C. Other current methods, also operating in the 1000°C range, involve the addition of a hydrocarbon gas such as methane;
Titanium carbide is contained in the coating deposit. These temperatures have a detrimental effect on the toughness of tool steel.
Reheating to re-increase toughness has a detrimental effect on tolerance. For example, tempered tools lose toughness between 500° and 600°C, stainless steel loses stability above 550°C,
Nickel-based superalloys undergo excessive aging above 600°C. By using lower-halides of the metals in question in the deposition reaction, deposition temperatures lower than the tempering temperatures of those metals can be used to deposit metal compound coatings of the type discussed above. was discovered. The term metal lower halide refers to metal halides in which the metal has a valence state (oxidation state) lower than the highest known valence state for the metal. For example, the maximum valence of titanium is 4, so it is TiCl ₄ . Therefore, the halogenated compounds of TiCl ₃ and TiCl _{2 in which titanium has a valence of 3 and 2} , respectively, are titanium lower halides;
In particular, titanium lower chlorides. Similarly, in the case of a metal whose maximum valence state is 5, a halogenated compound of the metal in which the metal has a valence of less than 5 is a lower halogenated compound of the metal. Canadian Patent No. 1087041 describes the application of hafnium carbide and hafnium nitride coatings by chemical vapor deposition. At that time, temperatures typically around 1300°C were required to produce hafnium coatings by chemical vapor deposition.
The patent describes the use of lower halides of hafnium in the deposition process,
This makes it possible to use temperatures as low as 900°C for the adhesion reaction. However, as discussed above, 900°C is still above the point of loss of toughness for many alloys that may be coated. Good coatings with good adhesion, texture and purity properties at good deposition rates using deposition temperatures lower than 900°C, e.g. temperatures of 890°C, are acceptable at the desired lower temperatures using metal lower halides. It has been found that by appropriately adjusting the flow rates and partial pressures of the reactants, suitable kinetic and thermodynamic conditions giving the reaction rate can be easily obtained. In a preferred embodiment, about 400 volumes of hydrogen and about
10 volumes of hydrogen chloride are passed at a controlled rate over a bed of titanium metal particles heated to about 500°C, and the resulting hydrogen/titanium chloride is mixed with 100 volumes of hydrogen and 150 volumes of nitrogen, and the gaseous A titanium nitride coating is produced on the substrate by passing the mixture over the substrate heated to about 600°C. Further improvements and modifications to the method include mixing nitrogen and hydrogen, passing the mixture over titanium metal particles, and mixing the hydrogen-nitrogen mixture with ammonia gas before passing it onto the substrate. Introduce. Varying the pressure of the gaseous mixture passing over the substrate, the pressure of the gas mixture around the substrate is approximately 4 mmHg.
Further improvements and modifications can be made by maintaining pressures below. The selection of pressure is made to produce a Knudsen flow of gas. "Knudsen flow" is a flow well known in the industry as "molecular flow", and the value of Knudsen number K (K = l/d; where d is the typical length of the flow and l is the mean free path) is This is achieved by maintaining the gaseous mixture at a pressure such that K>1.1. Here, the typical length d of the flow corresponds to the diameter in the case of a pipe with a circular cross section, for example. Thermodynamic analysis shows that lower halides (i.e., subhalides) of titanium, especially titanium dichloride (TiCl ₂ ) and titanium trichloride (TiCl ₃ ) (lower chlorides of titanium), have a greater negative free energy of reaction. It has been shown to provide higher potential for reactions involving deposition of TiN by CVD at low temperatures, thus providing greater potential for reactions involving deposition of TiN by CVD at low temperatures. actual,
The potential for titanium dichloride and titanium trichloride to react with nitrogen and hydrogen in a gas phase environment to deposit titanium nitride continues to increase until it reaches zero. Nevertheless, the reaction rate inhibits the deposition of titanium nitride at low temperatures. However, it was found that the reaction potential of TiCl ₂ and TiCl ₃ to form titanium nitride can be worked effectively in a steam atmosphere containing nitrogen and hydrogen using reaction temperatures ranging from 250 °C to 850 °C. . Depending on the deposition conditions used to overcome inadequate reaction rates, lower coating temperatures are possible, but the temperatures used may result in loss of toughness or hardness of the tool substrate or article being coated. The idea is to take full advantage of the advantage of suitable coating speeds at temperatures that do not occur. In the case of titanium, it is essential to keep the free energy of the reaction at or near a predetermined negative value so that the temperature at which the reaction and deposition of titanium nitride takes place is maintained within this temperature range. In particular, the higher the equilibrium constant (K _p ) of the reaction,
The free energy value of the reaction will be low. The partial pressures and flow rates of the reactants are thus maintained at carefully controlled levels so that the reaction is carried out over the desired temperature range. Furthermore, the use of ammonia in the chemical vapor deposition step maintains the equilibrium constant even higher,
Helps increase coating speed and quality. Titanium nitride is therefore made by combining titanium dichloride and/or titanium trichloride with hydrogen and nitrogen, optionally some ammonia, and the reactant TiCl ₂ at a suitable temperature that does not deleteriously affect the properties of the substrate. as well as
It is deposited by chemical vapor deposition by reacting with a flow rate that maintains the partial pressure of TiCl ₃ at a relatively high level. In that case, appropriate thermodynamic and kinetic factors are used to deposit titanium nitride at the desired temperature. Titanium dichloride and titanium trichloride are important components in the reaction to deposit titanium nitride because of the thermodynamic properties of their reactions. Titanium dichloride and titanium trichloride can be produced by reduction of titanium tetrachloride, but both such reductions
occurs in an amount less than that required to achieve suitably high rates of deposition. Of course, titanium dichloride and titanium trichloride can be obtained from other sources or simply sent to a chemical vapor deposition chamber for titanium nitride deposition. Alternatively, a second embodiment of the invention includes an in-situ preliminary step to produce titanium lower chloride by passing hydrogen chloride over titanium metal. Such reactions will yield titanium dichloride, titanium trichloride, and titanium tetrachloride, but their relative proportions in the gaseous reaction mixture will depend on the temperature, hydrogen, and partial pressure of the chlorinating agent, such as hydrogen chloride. can be varied by manipulating the titanium metal chlorination conditions. Less volatile than _TiCl4 in gas reaction mixtures
To increase the concentration of _TiCl2 and _TiCl3 , in situ titanium metal chlorination and TiN deposition can be performed in a two-step process, also at low pressure. Reducing the pressure during the chlorination process promotes the vaporization of lower chlorides, which have a higher vaporization temperature than _TiCl4 . This in turn allows chlorination to be carried out at lower temperatures, which in turn promotes the formation of lower chlorides. In the second step of the method, the titanium nitride deposition step, lower pressures in the vicinity of 4 mm Hg are used;
Operation is facilitated by improving the kinetic factors suitable for the deposition of titanium nitride onto a substrate. The invention will be better understood with reference to the following examples with reference to the drawings. Figure 1 contains thermodynamic values determined for possible reactions obtained with CVD coating methods using titanium chloride, indicating which reactants are preferred for reaction at which desired temperature ranges. In particular, Figure 1 shows the standard free energy versus temperature relationship for reactions 1, 2, and 3 below. TiCl ₄ (8)＋1/2N ₂ (8)＋2H ₂ (8) →TiN(s)＋4HCl(8) (1) TiCl ₃ (8)＋1/2N ₂ (8)＋3/2H ₂ (8)→TiN _s ＋3HCl(8) (2) TiCl ₂ (8)＋1/2N ₂ (8)＋H ₂ (8) →TiN _s ＋2HCl(8) (3) Figure 1 shows the range from −273℃ (0〓) to 1627℃ ( 1900〓）
Typical free energy values (ΔG°) for these reactions at reaction temperatures in the range of are shown. As shown,
The lower the free energy value, the greater the reaction potential, but beyond a certain point the reaction rate becomes inappropriate and there is a point at which it becomes difficult to make effective use of this potential. The graph shown in Figure 1 shows that TiCl ₄ is at 727°C.
Temperatures above (1000〓) can be effective for the adhesion of TiN, but when the reaction temperature drops to -273℃ (0〓), TiCl ₃ and TiCl ₂ will undergo the above reaction and
This indicates that it has the ability to participate in the TiN adhesion reaction. The probability of these two reactions is a reaction with a large negative free energy change (2)
and (3). The formation of TiN from TiCl ₂ or TiCl ₃ becomes more convenient as the temperature decreases. Nevertheless, at -273°C (absolute 0〓) any reaction would be very limited due to inadequate reaction rates. Furthermore, in order to cause a reaction at any temperature, physical process variables such as pressure and flow rate (i.e., reaction rate variables) and thermodynamics such as the equilibrium constant (K _p ), which is a component of the free energy value of the reaction, are required. It is necessary to manipulate the target value. Varying the reaction rate factors and thermodynamic values will result in reactions occurring at different temperatures. This may be better understood, in part, by considering the factors that control free energy values, particularly the relationship between free energy and the equilibrium constant (K _p ). 27 in the table
Reactions (1), (2) and (3) at temperatures within the range of °C to 1627 °C
The equilibrium constants (K _p ) of are listed.

[Table] K _p and G゜_T have the following relationship [reaction (3) is used for illustrative purposes]. (K _p ) _T = (P-HCl) ² × (P-TiN)/P-TiCl ₂ × (
P- _N2 )1/2xP- _H2 (4) Here, P-HCl represents the partial pressure of HCl at the reaction temperature T. ΔG゜_T = -PTIn(K _p ) _T (5) where R is the gas constant, T is the reaction rate, and In(K _p ) _T
is the natural logarithm of (K _p ) _T . As can be seen from equation (5), the free energy change (ΔG゜_T ) is proportional to the negative equilibrium constant. Therefore, as the equilibrium constant becomes larger, the negative value of the free energy change becomes larger, and the reaction potential becomes larger. Therefore, using TiCl ₃ from FIG. 1, in order for TiCl ₃ to participate in reaction (2) at a temperature of about 500° C., the free energy value needs to be in the range of −14 Kcal per mole of TiN. Using these free energies and temperature values, the temperature is then determined by equation (5).
The K _p value is determined and this set of partial pressures gives the combination of reactants for the reaction. Further, as discussed below, it has been found advantageous to introduce ammonia into the reaction of TiCl ₂ and TiCl ₃ to increase the rate of TiN deposition in reactions (2) and (3). A method apparatus for performing TiN deposition is described below, followed by examples for depositing TiN coatings on substrates at desired reaction temperatures by varying and manipulating process variables. FIG. 2 shows a process apparatus having two basic reaction chambers, a first chlorination chamber 1 and a coating chamber 2 downstream thereof and integrally connected thereto. The chlorination chamber is heated by a conventional resistance heating furnace 4.
The tool substrate 3 is placed in a coating chamber 2, and the chamber 2 is heated using a conventional resistance heating mechanism 5. Still alternatively, the substrate 3 is heated independently in the coating chamber using a conventional resistance heated cartridge heater 6. In chamber 1, a resistance heating furnace 4 heats titanium (Ti) metal chips from 150°C to 1100°C and sends HCl and _H2 through a flow meter 7 and over the heated titanium 8 to form _TiCl2 and _TiCl3. and hydrogen are produced according to the following synthetic reaction. xHCl(8)+Ti(s)→TiCl(w)+x/2H ₂ (6) (x=2 or 3) This reaction may also produce some amount of TiCl ₄ . However, this reaction factor can be reduced by providing a low partial pressure of HCl and using an appropriate combination of reaction temperature and relative flow rates of H ₂ and HCl to direct the reaction towards producing predominantly TiCl ₃ and TiCl ₂ . Adjust. TiCl ₂ and TiCl ₃ gases are transferred from chlorination chamber 1 to coating chamber 2 by a carrier gas such as hydrogen or helium.
and hydrogen and nitrogen are fed into the latter chamber through a flow meter to allow reactions (2) and (3) to proceed. Before reaching the chamber 2, the hydrogen and nitrogen are preheated by passing through the furnace 4 in an annular chamber around the reaction chamber 1. As discussed above, the K _p values for the desired reactions (2) and (3) at temperatures within the range of 250°C to 850°C are determined thermodynamically by equation (5), and the flow rates and fractions are determined thermodynamically by equation (5). A range of pressure values can be determined. It will be appreciated that the flow rate selected will affect the reaction rate.
The following examples were all carried out in equipment of the type generally illustrated in FIG. 2 to produce TiN coatings. However, unless otherwise specified, the apparatus was operated at 1 atm.

【table】

【table】

[Table] Furthermore, the quality of deposits and TiN during the above CVD reaction
It has been found that the deposition rate of can be improved by adding ammonia to the gaseous reaction mixture. In the following examples, substrate materials such as copper, stainless steel, and nickel-based superalloys are heated independently in a coating chamber by placing them on cartridge heaters. The temperature of the cartridge heater was regulated using a temperature controller. copper,
The temperature of the stainless steel and nickel-based superalloy substrate materials is monitored using separate thermocouples attached to their surfaces. The walls of the coating chamber are maintained at a constant temperature using a resistance furnace arrangement, as in the previous examples above and below. Of course, it is always important to maintain the coating chamber and its walls at a sufficiently high temperature to keep the metal lower halide in the gas phase and prevent any agglomeration from occurring on the walls. A coating time of 1 hour and an operating pressure of 1 atmosphere were used for all coating experiments summarized in the table.
In all of the examples given in the table, the same chlorination step in chamber 1 was carried out at 500° C. with a HCl flow rate of 10 ml/min and a H ₂ flow rate of 400 ml/min. Details of the deposition conditions used are shown in the table. From the above examples relating to the use of ammonia, ammonia is not only thermodynamically effective in increasing TiN deposition, as can be seen from the comparison of Examples 1 and 4, but also Examples 3 and 1,
It can be seen from the results given in the table that it improves the deposition rate of TiN, as also illustrated by the comparison of 2 and 4. The examples given in the table illustrate that it is advantageous to reduce the pressure in the chamber where coating occurs and during the chlorination process. From the table, the pressure in the coating chamber is 2
It will be seen that good coverage can be obtained by adding ammonia to mmHg and using the indicated flow rates. The table also illustrates, in a third example, the effect of introducing nitrogen in the first step of the process during chlorination. In the third example, the flow rate is 20ml of hydrogen,
Adequate coverage was obtained with 6 ml of HCl, 20 ml of N ₂ and a chamber pressure of 1.5 mmHg. Although the table illustrates examples operated at reduced pressure, it is recognized that introducing nitrogen in the first stage is also practical at atmospheric pressure. The procedure used for the coating will now be described in detail with particular reference to the first example of the table. The apparatus was evacuated to some extent by an exhaust system with all inlet gas flows turned off. A gas such as hydrogen or helium, which does not react with other materials, was flushed through the entire apparatus (hereinafter referred to as flash). Flushing continued until water vapor and oxygen were removed from the apparatus. Raise the temperature of titanium to 500℃ using furnace 4,
The temperature of the substrate 3 was raised to 600° C. by the heating mechanism 5. These temperatures were measured by appropriately placed thermocouples. The pressure inside the device was reduced. Hydrogen and hydrogen chloride were flowed over the titanium in a volume ratio of 40/12, and hydrogen, nitrogen and ammonia in a volume ratio of 20/10/3 were mixed with the gas obtained from the first stage. The mixed gases flowed into chamber 2 and a total pressure of approximately 2 mmHg was maintained. Temperature, gas flow and pressure were maintained for a suitable period of time, for example 1 hour. At the end of the process, the equipment is cooled, the gas stream is changed back to inert gas, and the workpiece is removed. Before chamber 2 is opened to admit atmospheric air, it is preferred to at least partially seal off part of stage (1) of the apparatus, thereby simplifying the subsequent flashing step. It will be appreciated that the above description deals with TiN coatings by way of example only. The low temperature deposition principle described above applies to zirconium nitride, titanium, and zirconium carbides and carbonitrides, vanadium,
It is equally applicable to the deposition of nitrides, carbides and carbonitrides of niobium, tantalum (metallic vanadium lower compounds) and chromium, molybdenum, tungsten (metallic lower chromium). In fact, the invention applies to those metals of Group B, Group B and Group B. This is because these metals have different valences, and when forming metal halides, valence states with lower free energies of formation can be utilized. In the case of carbide coatings, the reactant gases during the deposition reaction are hydrocarbons such as CH ₄ and H ₂ and metal lower halides.
In the case of carbonitride coatings, the reactant gases during the deposition reaction are hydrocarbons such as CH ₄ and H ₂ and N ₂ and/or
NH ₃ and metal lower halides. The substrates mentioned herein are examples and not the only ones. Other known substrates can also be coated using the method and apparatus of the present invention. Other known inert gases can also be used.

[Table] * In step 3, only the first 5 minutes of the entire 1-hour coating process are activated.
I flushed the ammonia and then stopped it.

【table】
No chlorine.
2 500 25 6 − 1 600
20 10 − Same as above.
3 500 20 6 20 1.5 600 20
− − Same as above but thinner

coating speed is slightly

decreased.

Claims (1)

[Scope of Claims] 1. A method for forming a coating of at least one metal compound from the group of metals titanium, zirconium, vanadium, niobium, tantalum, chromium, molybdenum and tungsten on a substrate, comprising: (a) in a reaction chamber; In the presence of a substrate, hydrogen and nitrogen;
A gaseous mixture consisting of hydrogen, nitrogen and ammonia; hydrogen and hydrocarbons; hydrogen, nitrogen and hydrocarbons; hydrogen, nitrogen and ammonia and/or hydrocarbon; and a gaseous mixture of metal lower halides are reacted, (b ) A method of forming a metal compound coating comprising maintaining the reaction temperature of the substrate and reaction chamber between 250° and 800°C, thereby depositing a metal nitride, metal carbide or metal carbonitride coating on the substrate. 2. The method according to claim 1, wherein the metal lower halide is a metal lower chloride. 3. The method of claim 1, wherein the metal lower halide is a titanium lower chloride, the gaseous mixture consists of hydrogen and nitrogen, and the coating deposited on the substrate is titanium nitride. 4. The method according to claim 3, wherein the gaseous mixture consists of hydrogen, nitrogen and ammonia. 5. The method according to claim 3, wherein the reaction temperature is within the range of 250° to 650°C. 6. The method according to claim 3, wherein the reaction temperature is within the range of 380° to 800°C. 7. The method according to claim 3 or 4, wherein the reaction temperature is within the range of 400° to 610°C. 8 Continuously flowing the gaseous reactants into the reaction chamber, but including the additional step of including ammonia gas in the initial flow of gaseous reactants and stopping the flow of all ammonia gas once deposition has begun. A method according to claim 3. 9. The method of claim 2, wherein the substrate comprises copper, stainless steel or a nickel-based superalloy. 10. A method for forming a coating of at least one metal compound from the group of metals titanium, zirconium, vanadium, niobium, tantalum, chromium, molybdenum and tungsten on a substrate, in a reaction zone upstream of the deposition reaction in a reaction chamber. An additional step to produce metal lower chlorides comprises: (a) passing gaseous hydrogen chloride and hydrogen over the metal in said reaction zone; (b) subjecting said reaction zone to a temperature in the range of 150° to 1100°C; (c) maintaining flow rates and partial pressures of hydrogen and hydrogen chloride in a manner that provides a partial pressure of hydrogen chloride to promote formation of metal lower chlorides; (d) in the presence of a substrate in the reaction chamber, hydrogen and nitrogen;
Reacting a gaseous mixture of metal lower halides with a mixture from a group of gaseous mixtures consisting of hydrogen, nitrogen, and ammonia; hydrogen and hydrocarbons; hydrogen, nitrogen, and hydrocarbons; hydrogen, nitrogen, ammonia, and hydrocarbons. (e) maintaining the reaction temperature of the substrate and the reaction chamber between 250° and 800°C, thereby depositing a metal nitride, metal carbide or metal carbonitride coating on the substrate; Law. 11. The method of claim 10, wherein the reaction zone is maintained within a temperature range of 500° to 850°C. 12 Claim 1 in which the metal is titanium
The method described in item 0. 13 The additional preliminary steps include (a) passing at least hydrogen halide over the metal in the reaction zone, (b) maintaining said reaction zone within a temperature range of 150° to 1100°C, and (c) passing the halogen on the metal. Claim 10 is a process comprising regulating and maintaining the flow of hydrogen hydride in a manner that promotes the formation of metal lower halides.
The method described in section. 14. The method of claim 13, further comprising introducing nitrogen gas into the process in the reaction zone where the metal lower halide is being formed. 15. The method of claim 13, further comprising introducing ammonia into the coating chamber and into the gaseous mixture for a limited time during the initial coating step. 16 The additional pre-step consists of passing a regulated stream of about 40 volumes of hydrogen and about 12 volumes of hydrogen chloride over a bed of titanium metal particles heated to about 500°C, and the deposition step consists of passing a regulated stream of about 40 volumes of hydrogen and about 12 volumes of hydrogen chloride over a bed of titanium metal particles heated to about 500°C. and 10 volumes of nitrogen, mixing the resulting hydrogen with titanium chloride gas and passing said gaseous mixture over a substrate heated to about 600°C, thereby depositing a titanium nitride coating on the substrate. , the method according to claim 13. 17. The method of claim 16, further comprising maintaining the gaseous mixture surrounding the substrate at a pressure of about 4 mm Hg or less. 18 Knudsen number K (K=l/d; however, l
17. The method of claim 16, further comprising maintaining the gaseous mixture at a pressure such that the mean free path and d is the representative length of the flow are K > 1.1. 19. The method of claim 16, further comprising introducing ammonia into the coating chamber and into the gaseous mixture for a limited time during the initial coating step. 20 A coating chamber having a gas inlet mechanism, a gas outlet mechanism, and a substrate heating mechanism for heating the substrate to a lower metal halide coating temperature; a halide gas inlet mechanism and a coating chamber for causing a reaction to produce a gaseous metal lower halide. A halogenation chamber is connected to the coating chamber within the coating chamber and has a reaction heating mechanism; a separation mechanism which, when open, promotes mixing of the metal halide and other process gases and which is removable and capable of being heated to the coating temperature; A metal compound coating manufacturing apparatus consisting of a metal particle container located in a chamber; and an access mechanism for a reaction chamber. 21. Apparatus according to claim 20, wherein the halogenation chamber is below the coating chamber. 22. The apparatus of claim 20, wherein the metal particle container comprises metal particles of titanium, zirconium, vanadium, niobium, tantalum, chromium, molybdenum or tungsten. 23. The device according to claim 22, wherein the metal particles are titanium or zirconium. 24. The apparatus of claim 20, wherein the coating chamber includes a flow regulation mechanism. 25. The apparatus of claim 20, wherein the halogenation chamber includes a flow control mechanism. 16. The apparatus of claim 20, wherein the halogenation chamber includes a pressure regulation mechanism. 27. The apparatus of claim 20, wherein the coating chamber includes a shelving mechanism for supporting the substrate. 28. The apparatus of claim 20, wherein the coating chamber includes a vacuum pump mechanism. 29. The apparatus of claim 28, wherein the vacuum pump mechanism includes a piston pump, a blower, a filter, and a scrubber. 30. The vacuum pump mechanism is separated from the coating chamber by an electro-pneumatic valve.
The equipment described in section. 31. The device of claim 20, wherein the separation mechanism is a metal disk. 32. Apparatus according to claim 31, wherein the metal disk is movable along the direction of the main axis of the halogenation chamber. 33. The apparatus of claim 20, wherein the halogenation chamber comprises a fused silica liner tube. 34. The apparatus of claim 20, wherein the coating chamber and the halogenation chamber are cylindrical. 35. The apparatus according to claim 34, wherein the coating chamber and the halogenation chamber are aligned in the axial direction. 36 Carrier gas inlet mechanism and gas outlet mechanism,
and a coating chamber having a substrate heating mechanism for heating the substrate to the lower metal halide coating temperature; a coating chamber having a halide gas inlet mechanism and a reaction heating mechanism for causing a reaction to produce a gaseous lower metal halide. a halogenation chamber coupled to the coating chamber within the halogenation chamber; a coating chamber including the halogenation chamber and a gas distribution mechanism coupled to the carrier gas inlet mechanism; a metal particle container located in the halogenation chamber; Metal cladding manufacturing equipment consisting of an ingress and egress mechanism for. 37. The apparatus of claim 36, wherein the coating chamber and the gas distribution mechanism are axially aligned. 38. The gas distribution mechanism consists of a set of distribution pipes, one of said distribution pipes being coupled to the halogenation chamber;
37. The apparatus of claim 36, wherein the other tube is coupled to a carrier gas inlet mechanism. 39. The apparatus of claim 38, wherein the distribution pipe is perforated. 40. The apparatus of claim 38, wherein the apparatus includes several sets of distribution tubes. 41. The apparatus of claim 38, wherein the halogenation chamber and carrier gas inlet mechanism are separated by a partition. 42. The apparatus of claim 41, wherein the halogenation chamber and carrier gas inlet mechanism are coaxial.