Al2O3 Second Firing Results

Al2O3 sintered fibers were taken out from the kiln. But as the problem occurred in the previous firing, after this firing there was no fibers found. Everything is broken into pieces. Have to find a solution for this problem.

Kneading Material

For the project Arg, another sample of body should be kneaded with fibers inside 6%. Hence, the kneading was started but after some time it was observed that the kneaded was stopped. There was a problem with the power outlet so that the kneading had to be started from the scratch.

Compression test for the third batch of project MH was done. It showed some interesting results. According to that clay with different kinds of silica had different strengths. According to strength,
1. Double layer Silica
2. Single layer Silica
3. Mixed Silica (Double and Single layer)

Sample Preparation

In the morning had a meeting with the co-supervisor and granted some work that has to be done within next few days. For one project (Arg) I have to do 3 kneadings.

1. with fibers - 6% - 5 hrs
2. with glass fibers - 6% - 5hrs
3. without fibers - 5 hrs

and also prepare samples for compression test on project MH and help my colleague for that.

So started work with kneading the sample without fibers.
Then sample preparation of MH for the compression test.

In the evening started to clean the small kneader after getting instructions from the co-supervisor.

Spaghetti Production

From the second batch of the Project MH, spaghetti of 1.5 and 0.5 was produced from ES 26g and 52g.

Production of 1.5 mm did not have any problem while 0.5 production (extrusion) had a problem. Time to time the extrusion was stopped because of some granules stuck inside or above the 0.5 die. So it had to be cleaned each and every time it stops making the process longer.

For Al2O3 project another 4 number of samples (fibers) were prepared and put to the furnace using another program which was changed according to the TGA results.

Fiber Project

After doing the sintering process with the fiber specimens, it is realized that there is something wrong either in the firing program or in the material. So a TG (thermogravimetric) analysis had to be done.

I have received the results from the TG analysis and drew the graph according that. There I could obviously see that the firing curve I used was wrong. Because the decomposition of the inner core of the fiber overlaps with the debinding process of the outer layer (The layer which should be remained after sintering).

So I changed the firing curve very carefully considering some factors according to the TG analysis results. I will sinter some more samples very sooner to check the effects.

Getting Better

The fingers which were squeezed in last year just before the Christmas days are now getting better. It seems that I am going to loose the two nails and at the same time coming new nails. Have to be so careful when working, not to stick with anything around. Otherwise the nails will be forcefully removed making a great disaster. ;)

I am really wondering how nicely the human body works. It is wonderful and amazing.

-- cheers

Rechecking Calibration

Calibration of the Sensors had been done by the service maintenance and I wanted to recheck the data I gathered earlier with the Micra-M device.

Problem: There were some transducers like 1400 bar transducer for what the Micra-M can't be calibrated because of the limitation of the calibration device we had. It can only go upto 550 bars since it is calibrated only till that pressure. but it can go upto 1000 bars. So tried to calibrate it until 1000 bars. But the values were getting a difference when the values are out of the range 200 - 500 bar. For the 350 bar sensor it was hard to calibrate Micra-M because it showed different input values each and every time it is rechecked.

Compression test of some ceramic rods were done according to a German norm. It is obvious that the sample preparation according to the norm is not that easy and it has an effect on the strength test.
The test was done on four types of batches and it is seen that one is really good in strength and the strength has been almost doubled than the last batch.

For another project, some tubes had to be sintered and one was put to the kiln to be debindered with the given temperature curve. To be certain about the results only one type of tubes was used rather than all the types. So one can be sure on the results when interpret them.

So at last it is another week end.. :)