Case 1.

Take APT powder 1000 grams , adding 1000 grams of water , stir , add 60 grams of lanthanum lanthanum continue to stir , steam heated and concentrated , dried and sieved to obtain lanthanum tungsten-coated powder . The prepared lanthanum tungsten-coated powder loaded boat , put through a hydrogen reduction furnace , heated to conduct a reduction temperature of 600 ℃, the reduction time is 2 hours. Then continue to a second temperature to 800 ℃ restore , restore time control in 3.5 hours , the hydrogen flow rate during 0.5m3 / h. Then lanthanum tungsten-coated powder into alcohol , glycerin lubricant mixing one hour after sifting , pressing, burn , pressing, calcining process conditions: loading powder quantity :650-700g / root , repression burn pressure : 60 ~ 80MPa sintering temperature : 1050 ~ 1400 ℃, sintering time : 40 ~ 60 minutes. Then using a conventional vertical melt sintering process , process conditions are as follows : vertical melt temperature : 2600 ~ 3000 ℃, holding time : 20 minutes Cooling time: 2 minutes , cooling time: 3 minutes . Finally finished processing , vertical melt billets after passing inspection , will be qualified blanks , into protected with a hydrogen furnace , then the sample temperature for 20 minutes to process requirements , as required swaging , and then processed to the desired product with different specifications .

Example 2.

Take tungsten powder 700 g , add 700 grams of water , stir , add 55 grams of lanthanum lanthanum continue to stir , steam heated and concentrated , dried and sieved to obtain lanthanum tungsten-coated powder . The prepared lanthanum tungsten-coated powder loaded boat , put through a hydrogen reduction furnace , heated to conduct a reduction temperature of 650 ℃, the reduction time 2 hours . Then continue to a second temperature to 900 ℃ restore , restore time control in four hours , during the hydrogen flow 0.5m3 / h. Other conditions are the same in Example 1 .

Example 3.

Take tungsten trioxide powder 850 g , add 850 grams of water , stir , add 58 grams of lanthanum lanthanum , continue stirring evenly, by steam heated and concentrated , dried and sieved to obtain lanthanum tungsten-coated powder . The prepared lanthanum tungsten-coated powder loaded boat , put through a hydrogen reduction furnace , heating get in a reduction temperature of 670 ℃, the reduction time 2.5 hours . Continue to warm to 970 ℃ for secondary reduction, reduction time control in five hours , during the hydrogen flow 0.5m3 / h. Other conditions are the same in Example 1 .


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Lanthanum tungsten electrode manufacturing method, comprising lanthanum tungsten-coated powder preparation , reduction, pressure type , melt down , and finished processing the preform , characterized in that : a. Using lanthanum acetate and including APT, tungsten and tungsten trioxide powder the solid material into a slurry with water mixed to prepare a lanthanum tungsten-coated powder ; b. lanthanum tungsten-coated powder decomposition of lanthanum was conducted in a hydrogen atmosphere , a reduction temperature is controlled at 600 ~ 700 ℃, time 2-3 hours , the second reduction temperature controlled at 800-970 ℃, reduction time 3-5 hours , the hydrogen flow control during the 0.5-2.0m3 / h.

The process of the invention include use of lanthanum acetate was added to APT, tungsten and tungsten trioxide powder of solid material , synthetic lanthanum tungsten-coated powder prepared by the method of lanthanum tungsten electrodes , instead of lanthanum nitrate used in the prior art tungsten-coated powder preparation Lanthanum the method of eliminating nitrogen oxides due to the gas generated by the decomposition of nitrate pollution. Since lanthanum acetate and lanthanum nitrate in the decomposition temperature differences, resulting in process effect differences. Prepared using lanthanum acetate, lanthanum tungsten-coated powder decomposition temperature greatly reduced , effectively simplify the process , and the method of the present invention is carried out in a hydrogen atmosphere using lanthanum decomposition avoids lanthanum compound is unstable in an oxidizing atmosphere of volatile , but also make the lanthanum salts decompose more fully, significantly improved vertical melt process the Chinese material conductive properties. With the lanthanum salt decomposition and reduction process to achieve continuous operation in the same device to complete two processes , greatly simplified the process, the reduction of working hours , saving energy , is an ideal method for producing lanthanum tungsten electrodes .


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1. Experimental Materials : APT, tungsten oxide , tungsten powder: purity of more than 99.5% ( by weight ) ; iron : content is less than 0.0025% ; Molybdenum : less than 0.01 % ; arsenic: content is less than 0.0025% ; alumina : content is less than 0.005% ; phosphorus: content is less than 0.01% ; oxidation residue traces of material size APT: 25 ~ 36μm; WO3: 8 ~ 9μm; tungsten powder : 2 ~ 2.5μm;

2. Lanthanum tungsten-coated powder Preparation: Materials used by Solid : H2O = 1:1 ratio mixing thoroughly stirred and then the prepared tungsten electrodes grade requirement ratio quantity of lanthanum acetate was added uniformly continued mixing uniformly , heated and concentrated by means of steam , drying, sieving step before being sent to restore.

3 Restore the prepared lanthanum tungsten-coated powder loaded boat after reduction furnace temperature decomposition and a secondary reduction, a reduction temperature of 600 ~ 700 ℃ , the restore time is 2 to 3 hours . Second reduction temperature : 800 ~ 970 ℃, time is 3-5 hours. These processes are carried out in a hydrogen atmosphere , the hydrogen flow control : 0.5 ~ 1.5m3 / h.

4 It will be restored after pressure type lanthanum tungsten powder coated aggregate batches for 2-5 hours , then physical and chemical analysis , to be lanthanum tungsten-coated powder has an average particle size of lanthanum oxide content and uniformity are in compliance with technical requirements , the addition of alcohol , glycerine lubricant mixing one hour after sifting , pressing, burn , pressing, calcining process conditions: loading powder quantity :650-700g / root , repression burn pressure : 60 ~ 80MPa, the sintering temperature : 1050 ~ 1400 ℃, sintering time : 40 ~ 60 minutes.

5 Vertical melt using conventional vertical melt sintering process , process conditions are as follows : vertical melt temperature : 2600 ~ 3000 ℃, holding time : 20 minutes Cooling time: 2 minutes , cooling time: 3 minutes .

6 Finished processing vertical melt billets after passing inspection , will be qualified blanks , into the furnace with hydrogen protection , according to the technological requirements of the sample temperature for 20 minutes , according to the requirements swaging , and then processed to different specifications of the finished product desired .


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Lanthanum tungsten electrode manufacturing method relates to a method mainly used for TIG ( tungsten inert gas welding ) and PLASMA ( plasma ) technology for metal welding , cutting, spray coating , smelting a method of manufacturing the tungsten electrode .

TIG tungsten electrode materials and PLSMA is a key technology in materials. Has been used in industry there are many types of tungsten electrodes . Tungsten electrodes widely used in the thoriated tungsten electrode shows better performance. However, due to which the body will produce thorium radiological hazards and the cumulative nature of the radioactive contamination of the environment , for people developed a cerium tungsten electrodes in an attempt to replace the technical field of TIG and PLSMA radioactive thorium tungsten electrode . Practical application shows that cerium tungsten electrodes in the small current welding , etc. successfully replaced thorium tungsten electrode , but in AC polarity , gas discharge light source , cathode emission materials, Shangmo completely replace thoriated tungsten electrodes , there is repeated arcing , poor reliability , burning rate, life expectancy and low defects. With the development of high-tech , machinery and electronics , petroleum, chemical , aerospace , shipbuilding , atomic energy and other fields, the metal being cut parent material type , shape, thickness and other requirements and more complex, the performance requirements for tungsten electrodes more increasingly harsh. Need to develop a better performance of the electrode in order to meet their needs. The results show that the addition of rare earth elements La, Y can effectively improve the performance of tungsten electrodes , especially lanthanum tungsten electrode has a long life and good performance from arc has broad application prospects .

Lanthanum tungsten electrode current manufacturing methods , the solid material is mainly used uniformly mixed with lanthanum nitrate , concentrated by heating , drying ( roasting ) , screening and other processes lanthanum tungsten-coated powder was prepared , and then restored , pressure type , vertical melting , billet and finished processing system to obtain lanthanum tungsten electrode . As is the use of nitrate -coated powder preparation method of the preparation process, will produce large amounts of NO pollution, and the decomposition temperature of the nitrate is high, it takes a long time to complete decomposition of calcination , resulting in process is difficult . And there may be generated due to decomposition of the nitrates incomplete , resulting in poor conductivity of billet , process performance deterioration phenomenon. Into the present application in September 1989 Patent No. 89107270.5 patent application , the disclosure of cerium acetate was prepared using the method of cerium tungsten electrodes , the method is effective to prevent the manufacturing process of cerium tungsten electrodes , preparing a NOx generated when powder coated environmental pollution , harsh operating conditions , but in the processing performance, there are still insufficient .


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