Six District students were among the 550 black students nationwide who are winners in the 18th annual National Achievement Scholarship Program for Outstanding Negro Students.

The students who attend high schools in 41 states, the District of Columbia and schools abroad are among more than 70,000 black students who entered this year's Achievement Scholarship competition by taking the 1980 qualifying test in their junior year.

They will receive $1.5 million in scholarships, supported by grants from 140 U.S. corporations, company foundations and professional associations, as well as contributions from individual donors.

The following District students were recipients of nonrenewable National Achievement $1,000 scholarships: Mark C. Alexander of A Street SE, Sidwell Friends School; Michele E. Booth of Euclid Street NW, Wellesley; Catherine L. Boucree of Geranium Street NW, Cromwell Academy; Thomas A. Duckenfield of Whittier Street NW, St. Albans School; Susan E. Rice of Massachusetts Avenue NW, National Cathedral School; and Nina D. Tolbert of 4708 Brooks St. NE, Spingarn Senior High.

Jennifer L. Johnson of Seat Pleasant, a student at St. Anthony's High School, and Arlene R. Keitzer of Upper Marlboro, a student at LaReine High School, also received National Achievement $1,000 scholarships.