Molybdenum Powder Molding And Sintering

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A method of preparing a dense metal molybdenum by forming and sintering using metal molybdenum powder as a raw material. It is the most commonly used method for the preparation of dense metal molybdenum in the industry.
The main process flow is:
Molybdenum powder → forming → low temperature sintering → high temperature sintering → dense metal molybdenum.

The process of compacting a metal powder into a compact having a shape, size, porosity, and strength by pressure. The methods for forming molybdenum powder mainly include two methods of metal molding and isostatic pressing.

metal die forming. This is a classic method of forming. It is suitable for forming smaller and more regular billets. Molybdenum powder is added with forming agent such as glycerin and alcohol mixture. After mixing, platinum powder is directly loaded into the steel mold and pressed into shape by the pressure of 196-294mpa on the oil press. The relative density of the pressed blank is 60%-65%.

Isostatic pressing. It is a new type of forming method. It can produce blanks and parts with uniform density. The isostatic pressures used in the industry mainly include static pressure and hot isostatic pressing of hydrostatic pressure, thick-walled elastic sheaths, and hydrostatic pressure is transmitted from the liquid in the high-pressure vessel to the molybdenum powder contained in the rubber soft membrane. And to achieve shaping, the isostatic pressing of the thick-walled elastic sheath is formed by transferring the pressure to the molybdenum powder by a thick-walled elastic bag set installed in the steel mold. Hot isostatic pressing combines forming and sintering, and it is suitable for forming large and complex shaped blanks or parts with a density close to the theoretical value.

Low-temperature sintering: The steel-formed billet is subjected to low-temperature pre-sintering in a muffle furnace to improve the strength and electrical conductivity of the metal billet. The sintering temperature is generally 1373-1573K, and the holding time is 20-40 min.

High temperature sintering: the blank produced by low temperature sintering (or isostatic forming) is consolidated into dense molybdenum metal with metal characteristics at high temperature. The high temperature sintering equipment commonly used in industry includes vacuum sintering furnace, vertical furnace, resistance furnace, induction furnace, electron beam furnace and so on. High temperature sintering temperature is generally 1973-2373k, the relative density of sintered molybdenum products can reach 90%-98%, which can be used as raw material for further processing, but also as a direct use of finished products.

Preparacian of compact molybdenum (preparacian of compact molybdenum) refers to the process of producing metal molybdenum ingots or molybdenum strips with compact structure and metal material properties with molybdenum powder or metal molybdenum blocks and molybdenum chips as raw materials, which is an integral part of molybdenum metallurgical process. Powder metallurgy was used for the materials of molybdenum powder, and smelting method was used for the materials of molybdenum block and molybdenum chip. Dense molybdenum is mainly used as raw material for molybdenum materials, electrodes, high-temperature resistant structural parts and steel additives.