SU1219255A1 - Method of producing titanium carbide powder - Google Patents

Description

The invention relates to powder metallurgy, in particular to methods for producing powders of refractory compounds, and can be used in non-ferrous metallurgy enterprises for the production of titanium carbide powder from waste titanium.

The purpose of the invention is to reduce energy consumption and simplify the process.

The proposed method consists in that heat treatment of titanium alloy chips is carried out in air at 850–1000 ° C for 0.5–2 h, then the chips are subjected to grinding, mixed with soot and heated in hydrogen to 1750–1850. temperature 0.5-1 hour

The mode of heat treatment in air at 850 ° C and a duration of 0.5 hours is due to the fact that at a lower temperature, the impregnation with implantation elements (0, Nj) throughout the entire thickness of the titanium chips is achieved due to the very long duration of the suspension (10 hours), which leads to increase the energy intensity of the process.

The choice of a temperature T 1000 C and a duration of 2 hours at this temperature as the upper limit of the temperature range and duration of the delay is due to the fact that through these process parameters the through penetration through the thickness of all practical sizes shavings of titanium alloys (up to 1.5 mm). A further increase in the temperature and duration of exposure is impractical, since the energy intensity of the process increases with constant quality of the final product and the content of nitrogen and oxygen, which are difficult to remove with further processing, which leads to complication of the process.

After grinding in a vibration mill for 0.2 hours, the intermediate product has an average grain size of 50-100 microns and a composition, in wt.%: Oxygen, 0.35-0.52; nitrogen 0.45-0.62; carbon 0.1-0.2; the rest of Ti.

Carbidization of a mixture of Ti-0-N with soot is carried out in a phyto-tube furnace gr in a hydrogen medium to a temperature of 1750-1850 ° C with a holding time at this temperature for 0.5-1 hours.

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The choice of a temperature and a holding time of 0.5 hours as the lower limits of the temperature and duration of the carbidization process is due to the fact that, at a lower temperature, titanium carbide with a bound carbon content of at least 17.5 wt.% Is formed for very long holding times. , which leads to an increase in the energy intensity of the process.

The choice of temperature 1850 С and the duration of exposure at this temperature for 1 h as the upper

the limit of carbidization and duration of the peak is due to the fact that with these parameters titanium carbide is produced with a content of bound carbon not

less than 17.5 wt.% for particles of Ti-0-N powder of 100 microns in size, and a further increase in the temperature and duration of the pinch leads to an increase in the energy intensity of the process with

slight improvement in the quality of the final product.

Example 1. The milling chips obtained for titanium alloy VTZ-1 with a size of 0.1

4.6 30 mm is heated in air in a muffle furnace at 850 ° C for 0.5 h. The resulting product is crushed and a mixture with carbon black (soot amount 24 wt.%) Is prepared in a vibratory mill with carbide balls for 0.5 h. Its oxygen content is 0.35 wt.%, Nitrogen 0.45 wt.%, The average particle size is 200 microns. Carbidization of the mixture is carried out

in a graphite-tube furnace in a hydrogen environment at T750 C for a period of 0.5 hours at this temperature. The titanium carbide sintered is ground in a vibratory mill for 0.3 h. 17.8; 18.2; 0.4; About 0.3. The process energy consumption is 9.5 kW.

Examples 2-5 implemented by

analogy with example 1 are shown in table.

Thus, according to the proposed method, titanium carbide was obtained, whose composition meets the requirements of TU-49-1978-78 and is close to the composition of TiC, obtained by a known method.

During the heat treatment of titanium alloy shavings in the air in a muffle furnace, the shaving of the penetration elements occurs throughout the thickness. The heat treatment regimes are established in which the content of the introduction elements is sufficient for satisfactory grinding of Ti-0-N, and, on the other hand, does not exceed 1.4 wt.%. The insignificant content of nitrogen and oxygen in Ti-0-N allows carbidization at lower temperatures and exposure times than in the known invention. Consequently, lowering the temperature of heat treatment and carbidization in

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If the process is carried out according to the proposed method, the energy consumption is reduced by more than 30% compared to what is known when using titanium alloys chips of similar size as a raw material. (The quality of titanium carbide powder remains at the same level). Holding the first

10 stages of the process in a muffle furnace in air, and the second stage in hydrogen, i.e. without the use of intelligent furnace equipment, it can significantly simplify the process design.

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In the case of heat treatment at 800 ° C for 0.4 h, the implantation elements do not saturate over the entire chip thickness, therefore, the quality of the final product, titanium carbide, is low. To obtain a TLC with a similar composition to the proposed method, a holding time at 800 ° C and 10 hours is required, which significantly increases the energy intensity of the process.

Compiled by L.Rodina Editor S.Patrusheva Tehred M.Nad

1190/16 Circulation 757 Subscription

VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5

Branch PPP Patent, Uzhgorod, st. Project, 4

Table continuation

Proofreader I. Muska

Claims (1)

METHOD FOR PRODUCING TITANIUM CARBIDE POWDER from chips, including its heat treatment, grinding, mixing with soot and subsequent heating of the mixture, characterized in that, in order to reduce energy consumption and simplify the process, heat treatment is carried out in air at 8501000 ° C for 0.5-2 h ", and heating is carried out in hydrogen up to 17501850 ° C with holding at this temperature for 0.5-1 hours.