A large pastel by Childe Hassam, the American impressionist; Chinese export porcelain; and some 60 pieces of an Imperial Russian Orlov vermeil (gilded silver) service, are among the 2,000-odd lots to be auctioned by C.G. Sloan & Co. Thursday through Sunday. The sale is expected to go over $1 million, according to Donald Webster, a co-owner of Sloan's.

More than 500 lots come from "Hickoryhurst" in Lake Erie, N.Y., the home of the collector Edward Michaels, who bought 18th-century English furniture, porcelains, Russian enamels and Oriental carpets at the turn of the century.

Russell Burke, Sloan's chief auctioneer, said the Russian vermeil service belongs to a well-known years ago in Poland. "He thought it was Polish. But as soon as I saw it, I recognized ti as the famous Imperial Russian service."

The catalogue explains: In 1770, Empress Catherine ordered a 3,000-piece dinner service from Jacques-nicholas Roettiers of France for Prince Gregory Orlov. In the middle of the 19th cnetury, it was copied for Czar Nicholas by Russian craftsmen. This set is part of the 19th-centery copy. The service includes chargers, platters, flatware and salts. The lots are expected to bring well over $12,000.

The "Holly Farm," a pastel by Childe Hassam (American impressionist, 1859-1965) is an 18-by-22 inch pastel. It is expected to auction for $40,000 to $50,000. The owners are descendants of a well-known painter, a friend who with Hassam visited the bush-Holly farm in Cos Cob, Conn., often. They intend to use the proceeds to have paintings of their distinguished ancestor restored for a major retrospective.

A gouache, "Crow Scout on Horseback," by Charles Marion Russell (American, 1864-1926), from the collection of the artist's wife, is expected to go for about the same as the Hassam. The auction also includes work by Rembrandt Peale, Joan Miro, Jules Feiffer, Ben Shahn and Edward Henry Potthast.

The Chinese Export porcelain, from a Philadelphia collector on Delancy Place, is, according to Webster, the finest collection the company has offered.

Last auction year (September-September), Sloan's sales were in excess of $4 million, according to Webster. The catalogue sale in December amounted to more than $850,000.