JPS60174862A - Composite spraying material containing ceramic whisker - Google Patents

Abstract

PURPOSE:To obtain a composite spraying material capable of spraying a needlelike fibrous ceramic material with reproducibility by mixing fine or hyperfine oxide ceramic particles with silicon nitride or carbide ceramic whiskers and calcining the mixture. CONSTITUTION:Fine or hyperfine oxide ceramic particles of <=0.5mum particle size are mixed with 10-40pts.wt. silicon nitride or carbide ceramic whiskers of 0.1-1mum diameter and 10-50mum length. The mixture is calcined and ground to <=150 mesh. The calcining temp., atmosphere and time are selected so that no reaction takes place between the ceramic materials.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to oxide ceramic thermal spray materials containing ceramic whiskers.

BACKGROUND ART Conventionally, a method has been widely used in which a thermal spray material is melted in a gas flame or plasma flame and sprayed onto the surface of a target material for coating.

Recently, solvent materials that are composites of multiple materials have been developed for the purpose of improving the properties of coatings or imparting functionality.

For example, Japanese Patent Application No. 58-28237 describes a ceramic whisker-containing thermal spray material manufactured by mixing and granulating silicon nitride or silicon carbide scar with a conventional thermal spray material. The sprayed coating obtained by spraying this thermal spraying material using conventional thermal spraying methods such as gas flame or plasma flame is intended to improve its adhesion and heat cycle resistance. A certain thermal spray coating can be obtained when the number of whisker overlapping parts is 1 to 3.
%, and when the whisker content increases to 3% or more, the phenomenon of separation of whiskers and powder spraying material becomes noticeable in gas flame or plasma flame, resulting in extremely unstable reproducibility of coating properties. was there.

The present invention has been made in view of the above points, and it is an object of the present invention to provide a composite thermal spraying material that can reproducibly spray ceramic acicular fiber materials such as silicon nitride whiskers and silicon carbide rice whiskers.

The configuration of the present invention will be explained below.

That is, the gist of the present invention is to provide a composite thermal sprayed material containing ceramic whiskers, which is characterized in that fine to ultrafine oxide ceramic particles and ceramic whiskers of silicon nitride or silicon carbide are mixed and fired. be.

Next, the present invention will be specifically explained.

Oxide ceramic fine particles to ultrafine particles with a particle size of several μm or less (preferably 0.5 μm or less) have a diameter of 0.1 μm or less. cgm
More than 1μm or less, length 10-50#m (preferably 1μm or less)
Depending on the type of oxide ceramic fine particles to be composited, 10 to 40 parts by weight (preferably 20 parts by weight or less) of silicon nitride or silicon carbide whiskers of 0 to 20/Jm).
The mixture is further fired under conditions of temperature, atmosphere, and time such that no substantial reaction occurs between the whiskers and the oxide ceramic fine particles, and the mixture is further heated to 150 meshes or less (preferably 200 meshes or less). crushed into
It consists of a step of classifying and removing fine particles of 5 μm (preferably 10 μm or less).

In addition, it is also possible to granulate the mixture of the above oxide ceramic fine particles and silicon nitride or silicon carbide whiskers to an appropriate particle size before firing, and in this case, pulverization after firing, air classification, etc. The means can be omitted.

Here, as the silicon nitride whisker or silicon carbide whisker used in the present invention, for example, the silicon nitride whisker or the silicon carbide whisker described in Japanese Patent Application No. 1983-1989. No. 118878, patent application No. 57-55196,
Patent application No. 57-96791 and Patent application No. 57-23334
The material obtained by No. 9 is pulverized to length, etc., as appropriate.
It is desirable to adjust and use it.

Examples of the present invention will be described below.

Example 1 10 parts by weight of silicon nitride whiskers having a diameter of 0.2 to 1 μm and a length of 10 to 50 μm were added to Ni0 fine powder (5 μm or less), mixed uniformly, and then fired in air at 1400° C. for 20 minutes. After pulverizing this into 200 meshes or less, it was air-classified to remove fine particles of 10 μm or less.

The spray material thus prepared was plasma sprayed onto a sandblasted SS-41 iron plate.

By using this thermal spray material, there is no longer a large amount of unwelded whiskers, powder, etc. that were previously observed.

Microscopic observation of the cross section of the film confirmed that the whiskers were uniformly dispersed within the film.

Example 2 Si sN4 whiskers with a diameter of 0.1 to 1.0 cgm and a length of 20 to 50 μm were dispersed in an aqueous solution of Z r OCA * Ca C12 adjusted to have a composition of Z r Ot ・8 mo 1% CaO and then add NH40
Co-precipitated with H20% aqueous solution, ZrO* 8mol1%C
A mixture of ao/10 wt% SNW was prepared.

After heating this at 800° C. for 3 hours, it was pulverized into 200 particles, and particles of 10 μm or less were removed by air classification.

The spray material thus prepared was plasma sprayed onto a sandblasted 5S-41 iron plate.

The sprayed coating obtained was quite porous, but there were no unwelded whiskers or powdery substances.

When this sample was subjected to a thermal shock test at 900° C. in water, it withstood more than 20 cycles. Also,
This was about 5 times as high as when the whiskers were not included (4 to 5 times), and the mixing effect due to uniform dispersion of the whiskers was confirmed.

Claims (1)

[Scope of Claims] 1. A composite thermal spray material containing ceramic whiskers, characterized in that fine to ultrafine oxide ceramic particles and ceramic whiskers of silicon nitride or silicon carbide are mixed and fired. 2. In the thermal spray material according to claim 1,
A composite thermal spraying material containing ceramic whiskers, characterized in that a mixture of fine to ultrafine oxide ceramic particles and ceramic whiskers of silicon nitride or silicon carbide is granulated in advance before firing. 3. In the solvent material according to claim 1,
A composite thermal spraying material containing ceramic whiskers, characterized in that fine to ultrafine oxide ceramic particles and ceramic whiskers of silicon nitride or silicon carbide are mixed, fired, pulverized, and air-classified.