Jiyas N, Akshay S D, Ardra S J, Sekhar Anand M R, Jayakrishnan M, Sasidharan Indu, K Bindu Kumar
Department of Mechanical Engineering, Government Engineering College, Barton Hill, Thiruvananthapuram, Kerala, India.
Department of Chemistry, Government Engineering College, Barton Hill, Thiruvananthapuram, Kerala, India.
Sci Rep. 2025 Jul 1;15(1):21804. doi: 10.1038/s41598-025-06775-3.
Amid growing environmental concerns over conventional brake pad materials, the need for sustainable and efficient alternatives has never been more pressing. This study investigates the innovative use of waste molluscan shells, naturally abundant in calcium carbonate, as eco-friendly substitutes for synthetic fillers in friction composites. Four shell species (Perna perna, Meretrix casta, gastropod, and Rocellaria dubia) were selected for evaluation, integrated into composite formulations alongside permanganate-treated kenaf fiber as reinforcement. Cashew friction dust and graphene oxide served as friction modifiers to optimize tribological performance. The elemental composition and structural characteristics of the shells were examined using Fourier-transform infrared spectroscopy, X-ray fluorescence, and X-ray diffraction, while thermogravimetric analysis assessed thermal stability. Five composite formulations, including a control sample with commercial calcium carbonate, were fabricated and tested for physical, mechanical, and tribological properties using a pin-on-disc apparatus in accordance with ASTM G99 standards. The top three formulations were further developed into brake pads and subjected to CHASE testing per SAE J661a protocols, including fade and recovery tests to evaluate frictional behavior, wear resistance, and thermal performance. Scanning electron microscopy was employed to analyze worn surface morphologies. The results demonstrate that molluscan shell-based composites offer a compelling green alternative to traditional friction materials, delivering superior performance in terms of friction stability, thermal resilience, and wear resistance. In particular, the P. perna shell powder additive composites emerged as a standout candidate, presenting an ideal synergy of tribological excellence and environmental responsibility. This research highlights the potential of waste-derived bio-fillers in advancing sustainable tribological systems and paves the way for next-generation eco-conscious brake pad technologies.
随着对传统刹车片材料的环境担忧日益增加，对可持续且高效替代品的需求从未如此迫切。本研究调查了富含碳酸钙的废弃软体动物壳作为摩擦复合材料中合成填料的环保替代品的创新用途。选择了四种贝壳种类（翡翠贻贝、西施舌、腹足纲动物和黑珊瑚）进行评估，并将其与经高锰酸盐处理的红麻纤维作为增强材料一起纳入复合材料配方中。腰果摩擦粉尘和氧化石墨烯用作摩擦改性剂以优化摩擦学性能。使用傅里叶变换红外光谱、X射线荧光光谱和X射线衍射对贝壳的元素组成和结构特征进行了研究，同时通过热重分析评估了热稳定性。制备了五种复合材料配方，包括一个含有商业碳酸钙的对照样品，并按照ASTM G99标准使用销盘式摩擦磨损试验机对其物理、机械和摩擦学性能进行了测试。排名前三的配方进一步制成刹车片，并按照SAE J661a协议进行CHASE测试，包括衰退和恢复测试，以评估摩擦行为、耐磨性和热性能。采用扫描电子显微镜分析磨损表面形态。结果表明，基于软体动物壳的复合材料为传统摩擦材料提供了一种引人注目的绿色替代品，在摩擦稳定性、热弹性和耐磨性方面具有卓越性能。特别是，翡翠贻贝壳粉添加剂复合材料成为突出的候选材料，展现出摩擦学卓越性能与环境责任的理想协同效应。本研究突出了废弃生物填料在推进可持续摩擦学系统方面的潜力，并为下一代具有生态意识的刹车片技术铺平了道路。
