SU821428A1 - Method of coating rotating quartz tube surface - Google Patents

Description

The invention relates to the deposition of coatings, in particular the deposition of coatings on the surface of quartz tubes used in high temperature processes, for example, in the electronics industry. For high-temperature processes for the production of semiconductor devices, large-sized tubular reactors with a diameter of 60–150 m and a length of up to 2 m of quartz glass are used; however, their service life is limited by the rapid growth of crystallization associated with the penetration process of various; from the lining of the furnaces and from the surrounding atmosphere into the glass. The consequence of crystallization is the subsequent RS. Failure of quartz tubes. Impurities penetrating the glass not only intensify the crystallization of quartz glass, but also, due to the significant diffusion coefficient of quartz glass, penetrate into the tubular space in which diffusion processes occur, which negatively affect the quality of silicon wafers. The known method of gas-flame spraying of refractory oxides such as the surface of metals, ceramics, including on parts in the form of rotation bodies. However, this method does not allow for a strong adhesion of coatings to a substrate on quartz glass due to the significant difference in the thermal expansion coefficients of the bonded materials and the high brittleness of quartz glass: the coating either falls off or there is cracking of quartz glass. The closest to the invention according to the technical essence and the achieved result is the method of coating the surface of a rotating quartz tube by preheating the surface at 400-700 ° C, gas-plasma spraying of a powder including SiOj, and heat treatment at 2000-3000 ° C. The rate of crystallization of these samples at 1500 ° C is 60-70 µm, the adhesion strength of the coating to the quartz pipe is six thermal cycles (the adhesion strength of the coating is determined by the number of thermal cycles maintained by the pipe without destruction when the temperature drops .1225 ° C to 250 s) C23. In general, products obtained in a known manner have a low adhesion strength of a coating to a quartz pipe and a rather high crystallization ability. The purpose of the invention is to increase the adhesion strength of the coating and reduce the crystallization capacity of the pipe. The goal is achieved by the fact that in a known method of coating a surface of a rotating quart of a twisted pipe by preheating the surface, gas-flame spraying of a powder of a material based on the flame of a burner, preliminary heating is performed at 200-500 ° C, and spraying powder lead in the following mode :; Linear speed of rotation of the quartz pipe m / min 16.2-19.2 Speed of the spraying device along the pipe, m / min 0.2-0.8 Pressure of the sprayed spray, atm0.2-0.35 Table 1 shows the compositions applied powders. Table

The following oxides are used as the feedstock: porous ioc with a main fraction of 50–60 µm and quartz segmented Si 02 with a main fraction of 50–60 µm, boric acid (dry) with a main fraction of 20–40 µm. Prc small quantities (up to 10%) of boron kislot can be used on fractions of 1-10 microns. Components are mixed mechanically. Powders are sprayed onto the surface of rotating quartz tubes using an UPN-5 or UPN-8 gas burner. Before spraying the powder, they are wiped with hydrolytic alcohol and short-term treatment (for 1-2 minutes with a pipe length E 1.52 m) of the pipe surface in a burner flame with a temperature of 3000 ° C. purpose of degreasing the surface. Example 1. Powder spraying is performed in the following linear mode: rotational speed of the quartz tube, m / min 16.2 Displacement velocity of the spraying device along the tube, m / min 0.2 Pressure of the spray gun, atm0.2 Temperature of the substrate preheating, OS200 The diameter of the burner surrounding the flame tube,% 110-125 diameter of the tube After coating, heat treatment (alloy) is carried out in the flame of the burner with a temperature of 3000 ° C for 1-3 minutes at a tube length of 1.2-2 m. Spray cut distance of a gas flame burner from a surface The quartz pipe stiles are 165-170 mm for pipes 1F 60-75 mm, 85-95 mm for 170-175 mm for pipes}. The flame of the flame enclosing the tube burns to 110-120% of the diameter of the quartz tube. EXAMPLE 2 Perform as in Example 1, except for the following modes: Linear velocity of rotation of the quartz tube, m / min 17.5 Speed of spraying device along the tube , m / min 0.5 The pressure of the spray powder, atm 0.25 P im Im 5. Performed as in example 1, except for the modes: A linear speed of rotation of the quartz tube, m / min 19.5. Table 2 shows the comparative data on the properties of the samples of uncoated and coated quartz pipes.

Uneven

TaVlitza2

0.5

3-5 0.5

70

3-5 6

Claims (1)

The claims of coating pouring and reducing the crystallization ability of the pipe, preliminary heating of the surface is carried out at 200-500 ° C, the powder is sprayed in the following mode: The linear velocity of rotation of the quartz pipe, m / min The velocity of the spray device along the pipe, m / min Pressure of the sprayed powder, atm 16,2-19,2 0.2-0.8 The method of coating the surface of a rotating quartz tube by pre-heating the surface, gas-flame spraying of a powder of a material based on AP ₂ C> s in a flame of a burner with a temperature of 3000 ° C, characterized in 0.2-0.035.