Microindentation Hardness-Secondary Dendritic Spacings Correlation with Casting Thermal Parameters in an Al-9wt.%Si Alloy

Innovative textile materials can be obtained by depositing different coatings. To improve the thermal properties of textiles, aluminum and zirconium (IV) oxides were deposited on the Nomex® fabric, basalt fabric, and cotton fabric with flame-retardant finishing using the magnetron sputtering method. An assessment of coating quality was conducted. Evenly coated fabric ensures that there are no places on the sample surface where the values of thermal parameters such as resistance to contact heat and radiant heat deviate significantly from the specified ones. Energy-dispersive spectroscopy was used for the analysis of modified fabric surfaces. Non-contact digital color imaging system DigiEye was also used. The criterion allowing one to compare surfaces and find which surface is more evenly coated was proposed. The best fabrics from the point of view of coating quality were basalt and cotton fabrics coated with aluminum as well as basalt fabric coated with zirconia. The probability of occurrence of places on the indicated sample surfaces where the values of thermal parameters (i.e., resistance to contact heat and radiant heat) deviated significantly from the specified ones was smaller for Nomex® and cotton fabrics coated with zirconia and Nomex® fabric coated with aluminum.

Download Full-text

Experimental estimation of transient evolution of three thermal parameters characterizing a dry friction interface

International Journal of Heat and Mass Transfer ◽

10.1016/j.ijheatmasstransfer.2021.120986 ◽

2021 ◽

Vol 169 ◽

pp. 120986

Author(s):

Mehdi-Belkacem Cherikh ◽

Jean-Gabriel Bauzin ◽

Najib Laraqi

Keyword(s):

Dry Friction ◽

Thermal Parameters ◽

Experimental Estimation

Download Full-text

Thermogravimetric Analysis (TGA) of Graphene Materials: Effect of Particle Size of Graphene, Graphene Oxide and Graphite on Thermal Parameters

C – Journal of Carbon Research ◽

10.3390/c7020041 ◽

2021 ◽

Vol 7 (2) ◽

pp. 41

Author(s):

Farzaneh Farivar ◽

Pei Lay Yap ◽

Ramesh Udayashankar Karunagaran ◽

Dusan Losic

Keyword(s):

Particle Size ◽

Quality Control ◽

Graphene Oxide ◽

Thermogravimetric Analysis ◽

Low Cost ◽

Thermal Parameters ◽

Carbon Decomposition ◽

Size Number ◽

Carbon Combustion ◽

Oxygen Groups

Thermogravimetric analysis (TGA) has been recognized as a simple and reliable analytical tool for characterization of industrially manufactured graphene powders. Thermal properties of graphene are dependent on many parameters such as particle size, number of layers, defects and presence of oxygen groups to improve the reliability of this method for quality control of graphene materials, therefore it is important to explore the influence of these parameters. This paper presents a comprehensive TGA study to determine the influence of different particle size of the three key materials including graphene, graphene oxide and graphite on their thermal parameters such as carbon decomposition range and its temperature of maximum mass change rate (Tmax). Results showed that Tmax values derived from the TGA-DTG carbon combustion peaks of these materials increasing from GO (558–616 °C), to graphene (659–713 °C) and followed by graphite (841–949 °C) The Tmax values derived from their respective DTG carbon combustion peaks increased as their particle size increased (28.6–120.2 µm for GO, 7.6–73.4 for graphene and 24.2–148.8 µm for graphite). The linear relationship between the Tmax values and the particle size of graphene and their key impurities (graphite and GO) confirmed in this study endows the use of TGA technique with more confidence to evaluate bulk graphene-related materials (GRMs) at low-cost, rapid, reliable and simple diagnostic tool for improved quality control of industrially manufactured GRMs including detection of “fake” graphene.

Download Full-text