Of firing temperature limits determine
From;    Author:Stand originally
1, concept

Base substrate of pottery and porcelain is in agglomeration process, the porosity drop off of base substrate, the density of base substrate increases ceaselessly, achieve base substrate porosity finally the smallest, the condition when density is the biggest calls agglomeration.

The temperature when agglomeration calls firing temperature, if continue to warm up, base substrate begins to be out of shape, bate, burn too expand. Firing temperature and had begun to burn the temperature limits between temperature to call firing temperature range.

2, determine method and measuring instrument implement

Will try put oven inside, below 105~110 ℃ stoving comes constant weight. Reserve to room temperature hind in the refrigeration inside desiccator. Say to take on balance dry the sample after is heavy. Say to take full after sucking kerosene, in kerosene sample is weighed. Full the in air sample after sucking kerosene is heavy. Put the sample that weighs good weight 105~110 ℃ kerosene eliminates inside oven, till sample medium kerosene is discharged,be over till.

In loading sample high temperature furnace by number order, one is scattered between the hearth when installing furnace and sample thin pink of thin to calcine quartz or Al2O3 pink. Begin to heat after outfit is good, press warm up the curve warms up, press booked sampling temperature sampling.

Heat preservation 15min is nodded in every sampling temperature, next from the quartz that sample takes out to be buried quickly in preheat inside electric stove in pink or Al2O3 pink, in order to make sure sample is in cooling process not scamper is cracked. Cold to after be close to room temperature, sample number, sampling temperature is recorded in the watch, examination sample has without craze, stick arenaceous wait for blemish. In putting 105~110 ℃ oven next, carbonado to constant weight. Take out sample to put desiccator inside, refrigeration comes room temperature. sample cent becomes two batches, 900 ℃ are the first batch below, determine its are full after sucking kerosene, be after kerosene in air heavy, the sample of 900 ℃ above is the 2nd batch, determine its are full bibulous hind reach again in water full bibulous hind weigh in air, computation is formulary:
= of the porosity after burning× 100%
In type: G0 -- the sample after burning is heavy in air, g;

G1 -- the sample after burning is in kerosene (water) in heavy, g;

G2 -- the kind after burning is full suck kerosene (water) hind heavy in air, g.

After the kill that by afore-mentioned formulary cipher out each temperature orders, it is abscissa with temperature, porosity and shrinkage are ordinate, the picture gives shrinkage and porosity curve, define firing temperature and firing temperature scope from the curve.