Short communicationFacile joining of SiC ceramics with screen-printed polycarbosilane without pressure
Introduction
Silicon carbide (SiC) ceramics have prominent comprehensive performance with high temperature resistance, high strength as well as hardness, and excellent corrosion resistance [[1], [2], [3], [4]], which makes SiC ceramic components widely used in the areas of aerospace industry, electronics and advanced nuclear systems [[5], [6], [7], [8]]. However, it is difficult to obtain SiC ceramic components with large and complex geometry because of their brittleness and high rigidity, which restricts practical application. In order to overcome this, it is necessary to develop the joining techniques of SiC ceramics. With the continuous efforts of researchers, many joining techniques have been developed to join SiC ceramics, such as nano-infiltration and transient eutectic-phase (NITE) joining [[9], [10], [11]], diffusion bonding [12,13], MAX-phase (M, early transition metal; A, A-group element; X, C or N) joining [14] and brazing joining [[15], [16], [17]]. Kim et al. adopted SiC tape to join SiC ceramics at 1850 °C under 20 MPa, and the flexural strength was reported to be 343 ± 53 MPa [11]. Chen et al. reported that the inactive AgCu filler metal was used to join chromium pre-coated SiC ceramics at 900 °C, leading to a shear strength of approximately 29.6 MPa [15]. In addition, joints produced by applying SiC preceramic polymers such as PCS, polysilazane (PSZ), polymethylsilane (PMS) and allylhydridopolycarbosilane (AHPCS) have some advantages over the ones using other joining techniques [[18], [19], [20], [21], [22]]. For example, the main composition of the joining interlayer is SiC, in accordance with the parent material, so the joint has good stability at high temperature, less stress concentration and excellent radiation resistance, especially favorable for the application in nuclear systems [19]. Zheng et al. reported the green state joining of SiC using mixture of PCS and SiC powder at 2000 °C, and the flexural strength of the joined samples increased from 180 to 250 MPa when the applied pressure on the green compacts increased from 35 to 138 MPa [18]. Colombo et al. adopted PCS to join SiC ceramics pressurelessly at 1200 °C, and the shear strength was reported to be less than 1 MPa [23]. Jeong et al. used PCS to join SiC composites at 1750 °C and 20 MPa, and the joints with flexural strength of about 120 MPa [24]. Khalifa et al. reported that the polymer AHPCS was used to join SiC ceramics at 1500 °C, leading to a shear strength of approximately 80 MPa [25]. In this paper, we adopted the precursor PCS of SiC as the joining material, via a facile screen printing method to join SiC ceramics at a relatively low temperature of 1500 °C without pressure.
Section snippets
Experimental procedure
The joining parent material is commercial chemical vapor deposited (CVD) SiC ceramics. Prior to the joining process, CVD-SiC ceramics were machined into approximately 10 × 10 × 3 mm3 monoliths and cleaned by ultrasonic with alcohol. The glass-like PCS solids (molecular weight: 1517, structural formula: (-SiHCH3-CH2-)n, Suzhou Sailife Ceramic Fiber Co., Ltd. Jiangsu, China), as the joining materials, were grinded to obtain fine and uniform powders. Mixture of refined PCS powders and alcohol was
Results and discussion
TG-DSC was carried out to understand the ceramization process of the joining material PCS (Fig. 2(a)). As can be seen from the TG curve, mass variation of PCS at low temperatures (<300 °C) is very small. In the temperature range of 300 ∼ 700 °C, the mass loses first and then the TG curve tends to reach a platform with the increasing temperature to 1280 °C. The overall mass loss is approximately 35.22%, which means that the ceramic yield of PCS used here is approximately 64.78%. The DSC curve in
Conclusions
In this work, SiC ceramics were successfully joined by a screen printing method with pure PCS as the joining material at a relatively low temperature of 1500 °C without pressure under Ar atmosphere. XRD pattern shows that the pyrolysis products of PCS have only pure SiC phase. The ceramic yield of PCS is approximately 64.78%. The interlayer is approximately 2 μm, which is more conducive to obtaining a relatively dense interlayer and less defects. And the average shear strength of the specimens
Declaration of Competing Interest
The authors report no declarations of interest.
Acknowledgements
This work was financially supported by National Key R&D Program of China (No. 2017YFB0702404), National Natural Science Foundation of China (No. 51832002) and Shenzhen Clean Energy Research Institute.
References (31)
- et al.
Thermal shock resistance and fracture toughness of liquid-phase-sintered SiC-based ceramics
J Eur Ceram Soc.
(2009) - et al.
Current status of SiC/SiC composites R&D
J Nucl Mater.
(1998) - et al.
Design and material issues for high performance SiCf/SiC-based fusion power cores
Fusion Eng Des.
(2001) - et al.
Compatibility of PIP SiCf/SiC with LiPb at 700°C
Fusion Eng Des.
(2010) - et al.
Effects of pyrolysis processes on the microstructures and mechanical properties of Cf/SiC composites using polycarbosilane
Mat Sci Eng A-Struct.
(2005) - et al.
The influence of sintering additives on the irradiation resistance of NITE SiC
J Nucl Mater.
(2011) - et al.
Effects of neutron irradiation on mechanical properties of silicon carbide composites fabricated by nano-infiltration and transient eutectic-phase process
J Nucl Mater.
(2014) - et al.
Microstructures of diffusion bonded SiC ceramics using Ti and Mo interlayers
J Nucl Mater.
(2013) - et al.
Effect of the polycarbosilane structure on its final ceramic yield
J Eur Ceram Soc.
(2008) - et al.
Synthesis of a novel preceramic polymer (V-PMS) and its performance in heat-resistant organic adhesives for joining SiC ceramic
J Eur Ceram Soc.
(2012)