What Is PC/ABS Alloy, and When Should You Choose It Over PC or ABS?

An alloy is a re-combination, not a compromise

PC/ABS is a blend of polycarbonate and acrylonitrile-butadiene-styrene. Rather than averaging the two materials, it uses phase control so that PC contributes impact strength and heat resistance while ABS contributes melt flow and lower cost, with a compatibiliser stabilising the interface between phases.

The practical result is a notched Charpy impact of roughly 45-60 kJ/m² at 23 °C — above most ABS grades — and a heat deflection temperature (1.82 MPa) of 95-115 °C, clearly above the ~85 °C of general-purpose ABS.

When PC/ABS is the right call

Electrical housings are the classic case: the part must survive drop impact, meet UL94 V-0, and accept a gloss or matte finish. Loading ABS with flame retardant degrades mechanical properties, while neat PC has high melt viscosity and residual stress that complicate thin-wall moulding. PC/ABS usually wins on that intersection.

Automotive interior trim follows the same logic: instrument panel retainers, upper door panels and decorative covers need heat resistance — no softening after sun load — together with fine grain surfaces.

When it is not

Where the part sees oils, solvents or plating baths, the PC phase is the weak point and stress cracking risk rises sharply. Long-term outdoor exposure calls for a weather-resistant grade with UV stabilisation; standard PC/ABS will yellow.

PC/ABS must also be dried: above roughly 0.02% moisture it hydrolyses in the barrel, producing brittle parts, silver streaking and a drop in impact strength. Dry for 3-4 hours at 90-100 °C.