Thermal Decomposition of Silicon Imide or Amide

In this process first SiCl4 is reacted with ammonia gas at a temperature range of -30.C to 70.C so as to produce silicon imide, tetramide monosilane and other related compounds. The formed materials converted to silicon nitride in special furnace at a temperature of 1600.C under nitrogen or ammonia […]

Vapour phase reaction of Silicon Halides with Ammonia

This method is used for producing sinterable silicon nitride powder with very high alpha phase content. In this process vapour phase ammonolysis of SiCl4 is carried out under diluted nitrogen atmosphere the temperature range of 1100 to 1300.C. The reaction may be given us as follows:
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Nitridation of metallic Silicon
Nitridation of metallic silicon is a common method of making silicon nitride powder. In this method the silicon is heated in a special furnace at a temperature of about 1300 to 1500.C in a nitrogen or ammonia atmosphere. Iron is used as a catalyst in this process to accelerate the […]

Silicon Nitride falls under Non oxide Ceramics group. This is a very important advanced structural ceramic raw material having exceptional mechanical and thermal properties. Silicon Nitride exists in two modifications
- Low temperature Alpha Form
- High temperature Beta Form
The Alpha-Beta transformation has an important contribution in the sintering process. There are 5 methods available for the production of […]

Lead-Zirconate-Titanate Powder Preparation
Sol-gel Method: In the fourth process Pb(NO3)2, ZrOCl2 and TiCl4 solutions are mixed in required quantity. To prevent the formation of PbCl2 sufficient quantity of NH4NO3 is added.
Co precipitation of the mixed solution is activated with the addition of a 12N ammonia solution. This yields a stable sol and it is […]

Lead-Zirconate-Titanate Powder Preparation
Sol-gel Method: In this third method ethanolic solution of zirconium isoporpoxide and titanium ethoxide is hydrolyzed with the help of dilute nitric acid and excess water. The solvents are distilled out and the residue is taken in water. To this zirconium titania hydroxide sol Pb(NO3)2 is added.
An emulsion is prepared […]

Lead-Zirconate-Titanate Powder Preparation
Sol-gel Method: In the second method required quantities of zirconium iso-propoxide and titanium ethoxide along with complexing agent of either acetic acid or acetyl acetone is mixed with a methanolic solution of lead acetate with continuous stirring. The prepared sol large amount of acetone is added so as to form a […]

Lead-Zirconate-Titanate Powder Preparation
Sol-gel Method: This method is a novel method of producing ultra fine and pure powder materials of advanced applications. Based on the Sol preparation technique and gel formation it can be classified into four different groups.
In this first method intimate mixture of zirconium iso-propoxide and titanium ethoxide with a complexing agent […]

Lead-Zirconate-Titanate Powder Preparation
Synthesis from alkoxide-acetate precursor method: This method is used to produce very high pure, extremely fine and stoichiometric composite PZT powder.
Lead acetate solution is mixed with an intimate mixture of zirconium and titanium tetra-n-butoxides. This causes a simultaneous hydrolysis of alkoxides. In this process a complex hydroxide acetate is obtained […]

Lead-Zirconate-Titanate Powder Preparation
Alkoxide Hydrolysis Method: In this method in ethanol solution first the compounds like lead isopropoxide, zirconium tetrabutoxide and titanium ethoxide are separately dissolved. The solutions arrived separately are then mixed together and refluxed for few hours in nitrogen atmosphere at about 74.C.
In the next stage the solution is hydrolyzed at […]