Kawasaki Steel Corporation

Keizou Okuno

Nobuo Totsuka

Tetsu Narutani

Masakatsu Yamazaki

Masaki Mabuchi

Junichi Mano

Katsunobu Okutani

Youzou Ogawa

Kouzou Fujiwara

The improved version of a chromated metal sheet has a chromate layer on at least one side of a metal substrate or a plated metal substrate and it is characterized in that the chromate layer has a chromium deposit of 10-200 mg/m.sup.2 per surface in terms of metallic Cr, that the chromate layer contains silica in an amount of 0.1-6.0 in terms of the weight ratio of SiO.sub.2 to Cr, and that the chromate layer contains at least one kind of lubricating particles selected from the group consisting of graphite, MoS.sub.2, BN, calcium stearate and an organic lubricating substance in an amount of 0.1-100 in terms of the weight ratio of the lubricating particles to Cr. The lubricating particles can have a surface layer capable of nonionic surface activating action, and this surface layer accounts for 1-70 wt % of the lubricating particles. The chromated metal sheet has sufficient lubricity to withstand press forming in the absence of lube oil coatings, has high enough electric conductivity to present no problems in spot weldability and groundability, and has sufficiently high corrosion resistance to withstand use in a naked state.

Chromated metal sheet having high corrosion resistance with improved

A method for sintering Mn--Zn ferrite green compacts is provided which includes a first heating step of raising the temperature from room temperature to 600.degree. C. within a period from 30 minutes to 5 hours, a second heating step of raising the temperature from 600.degree. C. to the sintering temperature and holding the sintering temperature until the start of cooling within a period shorter than 10 hours, and a cooling step of lowering the temperature to 150.degree. C. within a period longer than 3 hours, with the total period of the three steps being shorter than 20 hours. This method permits the efficient production in a short time of Mn--Zn ferrites having good magnetic properties.

Method for producing Mn-Zn ferrites

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Chiba, Japan

Keizou Okuno