CS232844B1 - Process for the production of doped coating materials - Google Patents

Abstract

The invention relates to the field of plasma technology and solves the problem of producing spray materials intended for thermal or plasma spraying. It is a method of producing refractory spray materials based on oxide ceramics, doped with an additive of 1 to 20% by weight of divalent to tetravalent metals, when the grains of the basic component are mixed with an aqueous suspension to a slurry with a particle size of less than 0.001 mm, flocculation is performed and the system is used or fired. The invention can also be used in the field of powder metallurgy.

Description

The present invention relates to a process for the production of refilled spray materials for heat or plasma spraying.

Many different methods of producing spray or plasma spray materials are currently used. The disadvantages of traditional production methods by melting the respective components in arc furnaces are eliminated by the method of producing doped coating materials; utilizing forces to bind the dopant particles to the grains of the Van der Waalsoy base material. A disadvantage of this process, however, is the difficulty of applying dopant to the grain of the base material, possibly to form a sufficiently stable bond between the grain and dopant particles.

These drawbacks are overcome by the process according to the invention, which consists in mixing the grains of the base material formed by one or more refractory metal oxides with the aqueous dopant suspension in the form of a metal, oxide or water-insoluble compound. With a particle size of less than 0.001 mm, preferably prepared by long-term dry milling and subsequent dispersion and addition of the peptizing agent, flocculation is performed and the system is dried or fired.

Said method greatly improves the adhesion of dopant particles to the grains of the base material, increasing the homogeneity of the resulting product and of the injections made.

The invention is further elucidated by means of several exemplary embodiments.

He did

The base coating material of white corundum having a grain size of 0.1 to 0.08 millimeters was subjected to dry grinding for 24 hours, after which the resulting product was dispersed in water with the addition of ammonium humate. The material was then mixed with 3 wt. TiO ₂ in an aqueous slurry containing 80% dry matter was flocculated with aluminum sulfate and the resulting product was dried. The resulting conglomerate were crushed and neřozpojené residues were separated on the sieve and returned to the wet process ^1. The maximum dimensions of the TiO ₂ particles were 0.0003 mm. During the tests it was found that the resulting content of TiO ₂ in the feed does not depend on the feed technique and the feeds are extremely chemically resistant.

Example 2

A material containing 97 wt. % of white corundum with a grain size of 0.063 to 0.050 millimeters and 3 wt. MnO ₂ having a particle size less than 0.0002 mm. However, instead of drying, calcination at 1300 degrees Celsius was included. The refractory binding of the dopant to the base grains was stronger than Example 1 and the percentage of dopant flow from the injection was about 20 to 30% less.

Example 3

In a similar manner to Example 2, a feed material was prepared using 94 wt. ZrSiO ₄ having a particle size of 0.12 to 0.18 mm and 6% by weight of ZrSiO ₄ ; CaCO ₃ with a maximum particle size of 0.001 mm. The resulting product, in which CaCO _{3 was} converted to the appropriate oxide by a hot process, showed very good homogeneity and the injections were of high quality despite the unusually large dimensions of the sprayed particles.

Claims (6)

CLAIMS 1. A process for the production of doped spray or plasma spray materials comprising from 80 to 99 wt. one or more refractory metal oxides having a grain size of 0.05 to 0.18 mm and 1 to 20 why. wt. dopant of a divalent to tetravalent metal group, characterized in that the grains of one or more refractory metal oxides, free of residual agglomerates, are intimately mixed with an aqueous dopant suspension having a particle size of less than 0.001 mm ¹ , preferably prepared by long-term dry milling and subsequent dispersion and the system is dried or fired. 2. A process according to claim 1, wherein the dopant is in the form of a metal, an oxide or a water-insoluble compound of the invention. Valuables which are converted into oxide by the heat process. ..... 3. A process according to claim 1, wherein the peptizing agent is ammonium hemiimate and the flocculation is performed with aluminum sulfate. 4. A process according to claim 1, wherein from 85 to 98% by weight of said base material is used. % of white corundum and 2 to 15 wt. TiO ₂ , 5. A process according to claim 1, wherein 95 to 99% by weight of the base material is used. % of white corundum and 1 to 5 wt. Mn, 0 ₂ . 6. A process according to claim 1, wherein from 88 to 98% by weight of said base material is used. % ZrSiO ₄ and 2 to 12 wt. CaCO ₃ .