Toyota Jidosha Kabushiki Kaisha

Toyo Aluminium Kabushiki Kaisha

Sumitomo Electric Industries, Limited

Honda Giken Kogyo Kabushiki Kaisha

Toyo Aluminum K.k.

Kazuo Fujii

Hirohisa Miura

Yasuhiro Yamada

Takashi Matsufuji

Mamoru Okamoto

Taro Tatsumi

Hiroyuki Horimura

Yoshinobu Takeda

Toshihiko Kaji

Hisao Hattori

Jun Kusui

Kyo Takahashi

Kosuke Doi

Koji Yamada

Kazuhiko Yokoe

A raw material for powder metallurgy contains at least 0.5 vol % and at most 10 vol % of alumina powder of which the sieve fraction with a sieve opening of 30 .mu.m is at most 0.1 wt %, and a remaining part of aluminum alloy powder. The moisture content of the alumina powder is at most 0.15 wt. % with respect to the alumina powder. Agglomeration of particles is thereby minimized or avoided. Highly reliable raw material for powder metallurgy having superior fatigue strength, impact resistance and wear resistance can be obtained. A method of preparing such a mixed powder raw material involves air classifying the powder materials, dry ball mixing the materials, and then annealing the mixed powder.

Raw material for powder metallurgy and manufacturing method thereof

A case nitrided aluminum product is produced by contacting an aluminum product with a nitriding agent at a part of a surface thereof at least, and by nitriding the aluminum product at the surface with an ambient gas at a temperature of a melting point of the aluminum product or less while keeping the aforementioned contact. The nitriding agent includes an aluminum powder, and the ambient gas virtually includes a nitrogen gas. The resulting nitriding layer has a depth of 5 micrometers or more, and it exhibits a case hardness of from 250 to 1,200 mHv. Thus, it is possible to form the deep and hard nitriding layer on the aluminum product with ease under the conditions where it has been said to be too difficult to nitride aluminum products. The case nitrided aluminum product can appropriately make sliding parts which require high wear resistance.

Nitriding agent

Case nitrided aluminum product, process for case nitriding the same, and

Growing community of inventors

Ohmihachiman, Japan

Kazuo Fujii