JPS6365752B2 - - Google Patents

Description

[Detailed Description of the Invention] [Subject of the Invention] The present invention relates to a thermal spray material, and in particular, the present invention relates to a thermal spray material, and in particular, a thermal spray coating that discolors,
This invention relates to a stable dark brown ceramic thermal spray material that does not fade.

[Prior Art] Enameling is a well-known technique for coloring and coating the surface of a substrate. The enameling method has the disadvantage that it cannot be applied to concrete, wood, etc. because it heats the base material.

Thermal spraying is a technique to improve this drawback.
Thermal spraying has the advantage that not only can the surface of the substrate be coated without changing the properties of the substrate, but also heat resistance, corrosion resistance, and abrasion resistance can be imparted to the coating by using ceramics as the thermal spraying material.

Depending on the purpose, thermal spray materials are required to have properties such as heat resistance, corrosion resistance, and abrasion resistance. If the purpose is to coat the surface of building materials etc., particularly high heat resistance is not required, and if used for interior materials etc., corrosion resistance will not be much of a problem. Instead, color tone becomes an important element. In addition, it must not discolor for a long period of time, and if it is used in places that are prone to wear, it must have hardness, wear resistance, etc.

Traditionally, thermal spray coating materials with decorative properties that give a beautiful appearance include black Al ₂ O ₃ /TiO ₂ and white
Al ₂ O ₃ , Al ₂ O ₃・C ₀ O exhibiting cobalt blue color
etc. are known, but their number is small.

The reason why there is so little colored thermal spray material is due to the fact that the color tone of the thermal spray material before and after thermal spraying is not necessarily the same. In particular, when thermal spraying ceramics is carried out using the plasma method, plasma is generated in a reducing atmosphere, so there are more oxygen vacancies than in a normal crystal lattice state, which causes color absorption, which causes problems after thermal spraying. It is believed that the overall color tone of the ceramic coating will be different from the color tone of the ceramic before spraying. Therefore, it is extremely difficult to predict the color tone obtained as a result of thermal spraying from the apparent color tone of the thermal spraying material before thermal spraying, and it is often unknown until thermal spraying is actually performed.

However, when performing thermal spraying, it is important to predict the color tone of the thermal spray coating before thermal spraying and to develop a thermal spray material that matches the desired color tone.

It is well known that each metal oxide generally has a unique color. For example, beryllium oxide BeO itself is white;
When a compound is made with Al ₂ O ₃ , SiO _{2 ,} etc., for example, 3BeO.Al _{2 O} 3.6SiO ₂ , which has the composition of beryl, exhibits the pale green color of beryl. In addition, MnO itself exhibits a green color, which is similar to CaO.
It also appears green when it forms a compound with SiO ₂ etc.
Saphire, known as a natural and artificial gemstone,
Ruby, spinel, quartz, amethyst, etc. are all due to the unique coloring of their constituent metal oxides.

However, thermal spray materials are generally sprayed at high temperatures. Furthermore, when the thermal spraying material is, for example, a mixture or compound of one or more metal oxides, when these materials are subjected to high-temperature thermal spraying, particularly plasma spraying, as mentioned above, a part of the composition may suffer from oxygen vacancies or the like due to the high temperature of the plasma. The color tone of the thermal spray material before thermal spraying is often different from the color tone after it is thermally sprayed.

[Objective of the Invention] In view of the above-mentioned problems with thermal spraying technology, the present invention has been developed to provide a thermal spray coating that does not damage the base material to be thermally sprayed, has sufficient hardness and abrasion resistance as a thermal spray coating for building materials, etc., and develops a dark brown color. The objective is to provide a thermal spray material that can

[Structure of the Invention] The thermal spray material of the present invention contains Cr ₂ O ₃ :1 to 30% by weight,
_Fe2O3 : 1 _to 20% by weight, ZnO: 5 to 50% by weight,
It is a new composition consisting _{of Al2O3} : 30 to 90% by weight.

Al ₂ O ₃ is a material with excellent heat resistance, high hardness, and wear resistance, but its thermal spray coating is white. The present invention utilizes the properties of Al ₂ O ₃ , and the composition and range of the above four components are selected in order to obtain a thermally sprayed coating that develops a dark brown color and to provide sufficient hardness and wear resistance. be.

The reason why the Cr ₂ O ₃ composition in the thermal spray material of the present invention is set to 1 to 30% by weight is that it is within the range necessary to develop a dark brown color when combined with the remaining components.

The color development mechanism of thermally sprayed coatings is complex, and it is thought that the components interact with each other. According to experiments, colors ranging from light dark brown to deep dark brown can be obtained with the above composition, but as ZnO increases from 5% to 50% by weight, and Fe ₂ O ₃ increases from 1% to 20% by weight. As the color changes, the colors change from light to dark, and the sense of solidity increases. By using ZnO and Fe ₂ O ₃ together, the melting point of the sprayed material is lowered, and the sprayed coating becomes dense and smooth. This further improves wear resistance.

Al ₂ O ₃ develops a dark brown color in association with the above components, and if it is less than 30% by weight, the hardness of the sprayed coating will be insufficient. Also, the upper limit is limited to 90% due to the relationship with the remaining ingredients.

The thermal spraying material of the present invention has a composition of Cr ₂ O ₃ ,
A mixture in which Fe ₂ O ₃ , ZnO, and Al ₂ O ₃ are mixed as single substances, or a granulated product granulated with a binder, and further the above mixture is melted, solidified,
Any form of ground granules can be used.

[Effects of the Invention] The thermal spraying material has a decorative effect that gives an aesthetic appearance to objects to be thermally sprayed, especially buildings made of wood, concrete, etc., and is dense and has practically sufficient hardness and abrasion resistance.

Example 1 17% by weight of dark brown Cr ₂ O ₃ , 9% by weight of reddish Fe ₂ O ₃ , 40% by weight of white ZnO and 34% by weight of white Al ₂ O ₃
The thermal spraying material that is uniformly mixed with % by weight (both are powders) is a powder that exhibits a dark brown color before thermal spraying. As a result of plasma spraying this thermal spraying material onto a concrete base material, the coated sprayed surface was given a deep dark brown, clear and beautiful appearance. This color tone was specified in advance by the builder, and was realized by using a composition prepared by the present inventor. The color tone of the thermally sprayed coating was deep dark brown, and this color tone did not change or fade over a long period of time, and had extremely stable weather resistance. The hardness and abrasion resistance were not much different from the following example.

Example 2 To carry out the dark brown thermal spray coating specified by the builder, Cr ₂ O ₃ = 28% by weight, Fe ₂ O ₃ = 15% by weight, ZnO =
A mixed powder spray material consisting of 7% by weight and 50% by weight of Al ₂ O ₃ was sprayed onto the external wall of a wooden building by plasma spraying. As a result, the coated thermally sprayed surface after thermal spraying had a deep and beautiful dark brown appearance, and this color tone was exactly the same as the color specified by the installer, which satisfied the installer's full satisfaction. Furthermore, this coating color did not change or fade at all even after three years had passed, proving that it was extremely stable.

The physical properties of this coating, such as hardness, were as follows.

Here, the hardness is determined by mirror polishing the sprayed coating surface and applying the load.
Micro-Vickers hardness was measured under the conditions of 100 g and a holding time of 15 seconds.

The wear rate was determined by projecting an abrasive onto the thermally sprayed coating using a sandblasting method and measuring the weight loss of the coated surface at that time. The blasting device used was that disclosed in Japanese Patent Application Laid-Open No. 51-6892. Alumina abrasive grains (particle size
JIS#24), projection amount 32Kg/min, projection speed
2500m/min, projection angle 30°, feeding speed of coated sample
It was blasted at a rate of 0.75m/min and a projection distance of 400mm.

Hardness Hv (100) 600-750 Wear rate 0.040 (g/cm ² ) As a comparative value, if Al ₂ O ₃ · TiO ₂ (40% by weight of TiO ₂ ), which is generally used as a thermal spray material, is shown, the thermal spray coating will be Hardness Hv (100) is 700-1000, wear rate is
It is 0.021 (g/cm ² ). This thermal spray material is ZnO,
Since it does not contain Fe ₂ O ₃ , it has high hardness, but this thermal spray coating is black and has a narrow application range.

The above characteristic values in the present invention are sufficient for coating building materials and the like.

Claims (1)

[Claims] 1 _Cr2O3 = 1-30 _% by weight, _Fe2O3 = 1-20% by weight, ZnO = 5-50% by _{weight , Al2O3} = 30-90% by weight
Ceramic sprayed material consisting of.