Thermophysical and radiative properties of pressureless sintered SiC and ZrB2-SiC laminates

Abstract

The evaluation of thermal and radiative properties of materials to be used as a hot part of thermal protection systems is a key issue for the design process of the HTC and UHTC components. Ceramic laminates with composition 100 vol%SiC and 80 vol%ZrB 2-20 vol%SiC were prepared by the tape casting technique and pressureless sintered. Thermal properties such as the thermal expansion coefficient, specific heat, thermal diffusivity and conductivity were measured; in addition the total emissivity was evaluated. A comparison of the thermal behavior of these two kinds of laminates is made. Moreover their possible integration in a unique structure is discussed.

Radiation heat transfer during hypersonic flight: A review of emissivity measurement and enhancement approaches of ultra‐high temperature ceramics

“…The maximum hemispherical emittance of this coating was recorded as ϵ h = 0.90 at 600 • C. This high emittance value can be attributed to the presence of unoxidized SiC. SiC is known for its high total hemispherical emittance values (ϵ h = 0.81-0.84) in the temperature range of 500-1300 • C. 48 The plasma-sprayed ZrB 2 -SiC sample demonstrated its next high emittance value (ϵ h = 0.80) at around ∼1000-1200 • C, due to the formation of the SiO 2 -abundant glassy layer. The emittance test in this study was performed up to 1200 • C using a calorimetric F I G U R E 9 ZrB 2 -SiC oxidation reaction sequence according to the model proposed by Fahrenholtz.…”

“…This high emittance value can be attributed to the presence of unoxidized SiC. SiC is known for its high total hemispherical emittance values ( ϵ h = 0.81–0.84) in the temperature range of 500–1300°C 48 . The plasma‐sprayed ZrB 2 ‐SiC sample demonstrated its next high emittance value ( ϵ h = 0.80) at around ∼1000–1200°C, due to the formation of the SiO 2 ‐abundant glassy layer.…”

“…Padovano et al 48 . prepared a novel ceramic laminate with a composition of 100 vol% SiC/80 vol% ZrB 2 ‐20 vol% SiC and measured the total emittance of this laminate in the temperature range 527–1527°C.…”

“…Padovano et al 48 prepared a novel ceramic laminate with a composition of 100 vol% SiC/80 vol% ZrB 2 -20 vol% SiC and measured the total emittance of this laminate in the temperature range 527-1527 • C. The authors observed that the emittance of SiC/ZrB 2 -SiC composite increased as a function of temperature up to a maximum value of ϵ h = 0.88 (at 1000 • C), then it plateaued. They also reported the emittance of SiC laminates as a nearly constant value (ϵ h = 0.85) across the temperature range up to 1527 • C. Therefore, high concentrations of unoxidized SiC contributed to the improved emittance of SiC/ZrB 2 -SiC laminates at high temperatures.…”

Synthesis and Properties of Silicon Carbide (Review)

“…Today, the synthesis of silicon carbide nanoparticles has become widespread among scientists around the world. There are many developed methods for the synthesis of silicon carbide nanoparticles, for example: sintering [13][14][15][16][17][18][19], combustion [20,21], selective method [22], sol-gel method [23][24][25][26], hydrothermal acid leaching [27], pyrolysis [28][29][30], pyrohydrolysis [31], low temperature synthesis [32,33], microwave synthesis [34][35][36][37], chemical vapor deposition [38][39][40][41][42], in situ growth [43,44], electric arc synthesis [45,46], etc.…”