Development of Calcium Sulphate Fiber‐Reinforced Polymeric Brake Pads for Vehicle Applications: Next‐Generation Friction Materials

ABSTRACT In response to the growing demand for sustainable and copper‐free friction materials, this study investigates the development of eco‐friendly brake pad composites reinforced with calcium sulphate fibers. Three copper and asbestos‐free brake pad formulations, Calcium Sulphate Fiber (CSF)—CSFA01, CSFB02, and CSFC03, were developed with 10 wt.% Calcium Sulphate Fibers of varying aspect ratios compared against a commercial brake pad (COMD04). Tribological properties were characterized using the SAE J661 Standard Chase test, while mechanical integrity and wear behavior were further examined using a Scanning Electron Microscope. Among the tested formulations, CSFC03 demonstrated a 20% lower wear loss, 3.6% higher recovery coefficient of friction, and 15% reduction in fade compared to COMD04. The coefficient of friction remained stable between 0.381 and 0.402 across all test regimes, reaffirming the composite's thermal and mechanical stability for demanding braking applications. The surface morphology also revealed better fiber‐matrix interaction and wear resistance. Four Multi‐Criteria Decision‐Making techniques—Analytic Hierarchy Process‐Extension Evaluation Method, Complex Proportional Assessment, Technique for Order of Preference by Similarity to Ideal Solution, and Multi‐Objective Optimization on the Basis of ratio analysis—were applied to rank the formulations, all consistently identifying the CSFC03 composite as the top‐performing green alternative. These results highlight the potential of calcium sulphate fibers as a sustainable, cost‐effective reinforcement for next‐generation eco‐friendly brake friction materials.