二月 2017 - Metal carbide powder,TiC cermet rod,TiCN cermet rod,Titanium oxide,cutting wheel Archive - Metal carbide powder,TiC cermet rod,TiCN cermet rod,Titanium oxide,cutting wheel
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Archive for 二月, 2017

microwave heating advantage:volumetric heating

Posted on: 二月 28th, 2017 by langfeng No Comments

During microwave heating, electromagnetic energy is converted to thermal energy within the sample; the mechanism is therefore essentially one of energy conversion, not just heat transfer. When microwaves penetrate and are converted to thermal energy within the material, heat energy is generated throughout the volume of the material; this results in volumetric heating and rapid, uniform heat-up of the bulk material.

The thermal gradient profile in a conventionally heated sample could be thought of as the reverse of that in microwave heating, in that the center could be slightly less hot than the outside because the thermal energy flows inward. In microwave heating, however, the center may be slightly hotter due to the internal energy conversion mechanisms, coupled with heat losses from the surfaces.

heat solution provider: microwave muffle furnace; microwave tube furnace; microwave lab furnace; microwave sintering furnace;microwave expansion furnace; microwave pyrolysis furnace;microwave pusher kiln; microwave rotary kiln;microwave high temperature melting furnace;microwave dental zirconia sintering furnace;

 

Advatages of sintering pure metal powders in Microwave furnace over conventional furnace

Posted on: 二月 27th, 2017 by langfeng No Comments

Application of microwaves for sintering of the pure metal powder in powder metallurgy process has been emerged as a potential process. The microwave sintering has significant advantages over conventional sintering because of different diffusion
mechanism involved in it. The following facts of microwave sintering can be summarized as:
1.The diffusion mechanisms in conventional and microwave sintering are quite different because of non thermal effects of microwave.
2.The smoother surface of powder compact is developed in short time by microwave sintering than conventional sintering.

3.The log (x/a) and log (t) have a linear relationship with a slope equals to 1/n where values of n different for conventional and microwave sintering which interprets existence of the different diffusion mechanisms.
4.The mechanical properties of microwave sintered compactedmetal power can be improved by pre working on metal powder as in the case of tungsten powder.  Langfeng high temperature microwave sintering furnace: LF-QS1512 1516

5.During microwave sintering, at lower temperatures surface diffusion and at higher temperatures volume diffusion are
dominant diffusion mechanisms as in the case of pure copper powder.

6.Thermal profile during microwave sintering in multimode microwave furnace depends upon particle size and porosity
present in compacted powder metal.  Langfeng high temperature microwave high vacuum sintering furnace: LF-ZK4516 ZK6016

7.The effect of oxidation on sintering of metal powder by microwave is less effective phenomenon in comparison to conventional sintering.

microwave muffle furnace; microwave tube furnace; microwave lab furnace; microwave sintering furnace;microwave expansion furnace; microwave pyrolysis furnace; microwave pusher kiln; microwave rotary kiln; microwave high temperature melting furnace; microwave dental zirconia sintering furnace;

Inhibition Mechanism of Carbide Grain Growth Inhibitor

Posted on: 二月 22nd, 2017 by langfeng No Comments

During the liquid-phase sintering, tungsten, carbon gradually dissolve in the liquid phase, at a certain temperature they can achieve homeostasis during dissolution-  precipitation .The solubility of tungsten carbide particles in the liquid phase is closely related to the particle size, the degree of surface energy and temperature. The greater size difference between the small particles and large particle, the greater difference between the saturated solubility in the liquid phase, so that the driving force of the tungsten carbide grains grows larger. With the refinement of the initial tungsten carbide, cobalt powder, especially for the tungsten carbide particle size less than 0.2 microns, tungsten carbide grains, during the sintering process, will grow rapidly to form coarse particles discontinuously, which significantly reduces the mechanical properties of carbide. Therefore, when the sintering of ultra-fine carbide, often we need to inhibit grain growth of tungsten carbide, to minimize and eliminate the non-continuous grain growth.

The mechanism of inhibitor: As inhibitors can fuse in the binder phase, whereby the liquid can be absorbed on the surface of tungsten carbide, hereby to diminish the area of contact with the liquid, and reduce the solid – liquid interfacial energy , so that the solubility of tungsten carbide particles mitigates, at the same time the differences of solubility among varying grains is reduced, the recrystallization grains of tungsten carbide is hindered. If under the sintering temperature of the WC-Co carbide, the solubility of tungsten carbide in a cobalt binder phase is 40%, while by the aid of inhibitor, the solubility of tungsten is reduced to 10%. The reduced solubility impact directly on the  dissolution and precipitation of tungsten carbide, at the same time, the inhibitors may be deposited on the tungsten-cobalt, tungsten carbide-tungsten carbide interface during precipitation, which further prevents the grain growth of tungsten carbide. Among the various grain growth inhibitors, the most effective inhibitors are vanadium carbide and chromium carbide,which can reduce the grain size of tungsten carbide to 0.15 microns.

Changsha Langfeng Metallic Material Co., Ltd. is one of very few leading manufacturer for metallic carbide powders:

carbide powder: Chromium Carbide Cr3C2 , Hafnium Carbide HfC, Molybdenum Carbide Mo2C, Niobium Carbide NbC, Tantalum Carbide Tac, Titanium Carbide TiC, Vanadium Carbide VC, Zirconium Carbide ZrC, Titanium Carbide Nitrides Ti (C,N); (Ta,Nb)C powder, (W,Ti)C powder, (W,Ta)C powder, (Ti,Ta)C powder,(W,Ti ,Ta)C powder, (W,Ti,Ta,Nb)C powder

Different types of grain inhibitors have different effects on the carbide performance, while adding more than one grain inhibitors is more favorable to enhance the overall performance of carbide. Adding vanadium carbide alone can significantly improve the hardness of the alloy, but will decline its strength, while adding chromium carbide alone can significantly improve the strength and corrosion resistance of ultra-fine cemented carbide and keep the hardness, therefore, vanadium carbide and chromium carbide are the most popular inhibitors to produce of ultra-fine carbide, and the combination of the two can play the best, generally the adding amount is of 1% or less.

 

 

Factors Affecting Sintering Quality of Powder Products

Posted on: 二月 16th, 2017 by langfeng No Comments

carbide powder sintering process

There are many factors that affect the performance of the sintered body, mainly the properties of the powder body, the forming conditions and the conditions of sintering. Sintering conditions include heating rate, sintering temperature and time, cooling rate, sintering atmosphere and sintering pressure conditions.
The sintering temperature and the length of the length of the sintered body of the porosity, density, strength and hardness. Sintering temperature is too high and too long, will reduce product performance, and even products over burned defects; sintering temperature is too low or too short, the product will be due to undercurrent caused by performance degradation.

For more information please link:www.metalcarbidepowder.com, please contact:angela@metalcarbidepowder.com

Composite carbide powders in cermets

Posted on: 二月 7th, 2017 by langfeng No Comments

(W,Ti,Ta,Nb)C powder

Cermets are composites produced by a combination of a ceramic and a metal. Cermets were the results of concerted efforts to develop an ideal material for high-temperature applications like jet engine turbine blades. These applications require a combination of high hardness, wear resistance and creep properties along with a significant improvement in toughness. Cermets bring together the useful characteristics of ceramics such as hardness, oxidation and heat resistance of carbides, nitrides and carbonitrides with binders, usually cobalt and nickel.

They can be represented by the general formula (Ti,Ta,Nb,W,Mo)(C,N)-(Co,Ni). The different elements form compounds like carbides, nitrides or carbonitrides and contribute to various properties. For example, Mo2C gives improved wettability of Ti(C,N) IN cermets, while TiC, Ti(C,N) give higher hardness than WC, lower thermal conductivity and lower solubility in ferrous alloys, a main component in cermets.

For more information please link:www.langfengmetal.com, please contact:angela@metalcarbidepowder.com