A RECORDING THERMOBALANCE FOR MATERIALS RESEARCH. PART 1. CONSTANT HEATING RATE THERMOGRAVIMETRY TO 1400C
Abstract
The report describes a means of modifying a recording thermobalance for routine constant heating rate thermogravimetry to 1400C with an optional temperature capability of 1750C. During operation, a sample is suspended beneath a linear variable differential transformer (LVDT) system by precision springs. Any sample weight change varies the relative position of the springs resulting in a proportional voltage being generated by the LVDT system. The conditioned voltage is then plotted on the Y(1) axis of an X, Y(1), Y(2) recorder. Temperature is recorded on the X carriage axis via a platinum, platinum+13% rhodium, platinum (ground) thermocouple placed into the sample powder. A synchronous time base generator supplies a time readout for the Y(2) axis. The constant heating rate is closely regulated by a spherical furnace/ SCR controller/time base recorder system. The atmosphere of the suspension chamber is air-freed and helium-filled by room temperature evacuation/purge cycles before the run. A run typically involves a -325 sieve 80 mgm dried powder sample to 1400C at 8.5C/min in helium purging flow. Recorder ranges are typically 0-25 mg/5 inch, 0-1400C/20 inch, and 0-200 min/5 inch. Typical thermograms are given for phenolic resin and polybenzimidazole/carbon cloth laminate samples.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1968
- Accession Number
- AD0675151
Entities
People
- Nicholas J. Olson
Organizations
- University of Dayton