Platinum alloy for ornaments and preparation method thereof

The platinum alloy comprises the following components in percentage by weight: 95%-96.8% of platinum (Pt), 1.5%-2.5% of palladium (Pd), 1%-1.2% of copper (Cu), 0.5%-0.8% of gallium (Ga) and 0.05%-0.1% of zinc (Zn). The preparation method comprises the following steps: (1) preparing a Cu-Ga-Zn intermediate alloy: heating and melting Cu, Ga and Zn in a vacuum induction melting furnace to obtain an intermediate alloy material; (2) smelting a Pt alloy cast ingot: putting Pt, Pd and an intermediate alloy into a smelting furnace together, heating until all metals are molten and uniformly mixed, and casting into a mold to form a platinum alloy cast ingot; (3) preparing the platinum alloy for the ornament: rolling the cast ingot obtained in the step (2) for multiple times to obtain the platinum alloy for the ornament; the platinum alloy disclosed by the invention has good mechanical properties, good color and luster and lower density, the cost is lower than that of the platinum alloy in the current market, and the co