| 主权项 |
1. A method for producing a water-resistant aluminum nitride powder by surface treatment of aluminum nitride powder particles having yttria on a surface thereof as a result of a production process thereof, the method comprising the successive steps of:
(i) making an aluminum nitride powder contact with an acid solution which can dissolve yttria, wherein yttria exists at least on a particle surface of the aluminum nitride powder; (ii) removing the acid from the aluminum nitride powder; and (iii) making the aluminum nitride powder contact with a phosphorus acid compound, wherein an amount of yttria which remains on the surface of the aluminum nitride powder after the step (i) is determined by carrying out the following successive steps of (a) to (e) on the aluminum nitride powder filtered, washed with water, and dried after the step (i) and is no more than 1000 mg per 100 g of the aluminum nitride powder filtered, washed with water, and dried:
(a) adding 10 g of the aluminum nitride powder filtered, washed with water, and dried to 25 mL of 1 mol/L hydrochloric acid in a 50 mL vial bottle at 25° C.;(b) holding the vial bottle in a ultrasonic bath and sonicating the vial bottle at 43 kHz for 30 minutes at 25° C.;(c) filtering the content of the vial bottle and thereby obtaining a filtrate;(d) measuring yttrium content in the filtrate by means of inductively coupled plasma atomic emission spectrometry; and(e) converting the yttrium content in the filtrate into the content in terms of yttria. |
