The invention relates to piston pairs and metering pumps on the basis thereof, to the manufacture of devices and parts thereof, and in particular to a method for processing cylindrical surfaces of parts consisting of a crystal on the basis of α-modification of aluminium oxide. The piston pair comprises an outer and an inner parts consisting of a crystal on the basis of the modification of aluminium oxide, preferably a monocrystal of leucosapphire with a roughness of the contact working surfaces Ra of 2-5 Angstroem. Smoothness of the surface is achieved by a processing method comprising drilling of preliminary semifinished products of parts consisting of a crystal with the aid of a diamond tool, three-stage mechanical processing of the surface with the diamond tool in the presence of cutting fluids and then decreasing the grain size of the abrasive, removing the internal stress in the semifinished products by means of an annealing method in a muffle furnace, processing the surface using a semi-soft or soft buffing wheel or a lapping tool with a diamond grain size of 5/3 and/or 1/0 μm using jewellers rouge, and tribochemical polishing of the surface using a polishing material on the basis of colloidal SiO2. The invention makes it possible to increase the service life of piston pairs used in metering pumps and to maintain for a longer period of time the accuracy of metering of metered liquids by virtue of reducing the coefficient of friction of rubbing surfaces.Изобретение относится к плунжерным парам и насосам-дозаторам на их основе, к изготовлению устройств и их частей, в частности к способу обработки цилиндрических поверхностей деталей из кристалла на основе α-модификации оксида алюминия. Плунжерная пара содержит наружную и внутреннюю детали из кристалла на основе α-модификации оксида алюминия, предпочтительно монокристалла лейкосапфира, с шероховатостью контактирующих рабочих поверхностей Ra 2-5 Å. Гладкость поверхности достигается способом обработки, включающем вы
