Hot Gas Blower (Cyberstar)

About

11-BM has a dedicated Cyberstar Hot Gas Blower. This can be used to heat small diameter capillary samples from ambient temperature to ~ 950 °C

About

Temperature Range and Ramp Rate.

ambient temperature to ~ 950 °C
Max ramp rate on heating & cooling is 5 deg C/min (300 C/hour)

Users should plan experiments to incorporate these heating and cooling ramp times.

11-BM Hot Gas Blower Image

Temperature Profile & Alignment

Temperature Calibration

Al2O3 Thermal Expansion

In-situ calibration of the hot gas blower was performed using the known thermal expansion of Al2O3 alumina a & c unit cell parameters as a function of temperature.

Full powder diffraction patterns were collected for select "nominal" set temperatures between 100 - 950 C at 11-BM using a 0.5 mm diameter fused quartz capillary packed with Al2O3 powder (NIST SRM 676a).

Refinements were performed against data from each nominal temperature to determine a & c unit cell parameters.

Based on the initial room temperature 25 C lattice values and published thermal expansion equations (below, see Reference 1), "real" observed sample temperatures were then calculated independently for each set of 'a & c unit cell terms.

The thermal expansion equation used for the a axis of Al203 (range 293-1900 K) is:

delta(a)/a (%) = -0.176 + (5.431E-4 * T) + (2.150-7 * T^2) - (2.810E-11 * T^3) (T/K)
assuming a room-temperature lattice parameter of a = 4.7592 A

The thermal expansion equation used for the c axis of Al203 (range 293-1900 K) is:

delta(c)/c (%) = -0.192 + (5.927E-4 * T) + (2.142E-7 * T^2) - (2.207E-11 * T^3) (T/K)
assuming a room-temperature lattice parameter of c = 12.9934 A

Finally, plotting observed vs nominal set temperatures for the Al2O3 data gives a correction curve and equation for other hot air blower measurements at 11-BM under similar experimental conditions.

These results (from July 2012) are shown below. These calibration data are kindly shared by Jae-Hyuk Her, GE Global Research.

Corrected temperature values calculated from calibration equation:
T_observed(K) = 0.9479*T_nominal(K) + 12.67

Nominal (Set) 	  Observed 	     Set - Obs
deg C	deg K	  deg C	 deg K		deg
 25	 298	   25	  295	  	  0
100	 373	   93	  366		 -7
200	 473	  188	  461		-12
300	 573	  283	  556		-17
400	 673	  378	  651		-22
500	 773	  472	  745		-28
600	 873	  567	  840		-33
700	 973	  662	  935		-38
800	1073	  757	 1030		-43
900	1173	  852	 1125		-48
950	1223	  899	 1172		-51

Reference 1 = J. Appl. Cryst. (1993). 26, 77-81

Phase Transitions

The temperature calibration of the hot gas blower was also studied using in-situ diffraction measurements of several known phase transitions. These results (from ~ 2011) are posted below.