Professor Jan Czochralski, inventor of "Czochralski" method.
Jan Czochralski was born on 23 October 1885 in Kcynia, which was then under the Prussian domination. He was the eight child of Franciszek and Marta Czochralski. He started the education at teachers' seminar in Kcynia. He was mostly interested in chemistry during his school days. After graduating the school he moved to Krotoszyn, to work in a drugstore and to study chemistry on his own. Later, he moved to Berlin and in 1904 began to work in the pharmacy and drugstore of Dr. A. Herbrand in Altglienicke. He carried out analyses of ores, oils, greases and metals. Then he worked for a short period in the laboratory of Kunheim and Co. in Niederschöneweide near Berlin and then in Allgemeine Elektricitäts-Gesellschaft (AEG). The job in Kabelwerk Oberspree and the two years spent in their research laboratories prepared him to become head of the laboratory of steel and iron research. This laboratory dealt with the checking the quality and purity of metals and alloys and was engaged in the refinement of copper. Simultaneously he attended lectures on chemistry at the Charlottenburg Polytechnic near Berlin. In about 1910 he obtained the title of chemist-engineer. From 1911 to 1914 he was an assistant of Wichard von Moellendorff with whom he published his first paper devoted to the crystallography of metals, or more precisely to dislocation theory ("Technologische Schluesse aus Kristallographie der Metalle" ["Technological conclusions from metal crystallography"], Zeitschrift des Vereines Deutscher Ingenieure 57, 931-935, 1014-1020 (1913).
The main task of Czochralski was the introduction of aluminium to electrical engineering i.e. pioneering works on the technology of the production of sheets, wires and pressings of aluminum, the study of aluminum alloys, and standardisation of metallographic studies. Metals and metallography became Czochralski's passion. His achievements were outstanding and opened new roads in metallurgical science and technology.
DISCOVERY OF THE CZOCHRALSKI METHOD
The Czochralski method of growing single crystals brought Jan Czochralski his greatest publicity. The method was developed in 1916 and was initially used to measure of crystallisation rate of metals. The method was developed as a result of an accident and through Czochralski's careful observation. One evening he left aside a crucible with molten tin and returned to writing notes on the study carried out on a crystallisation study. At some moment, lost in thoughts, instead of dipping his pen in the inkpot, he dipped it in the crucible and withdrew it quickly. He observed then a thin thread of solidified metal hanging at the tip of the nib. The nib slot, in which crystallisation was initiated, was replaced by a special narrow capillary and in some cases by a seed of the growing crystal. Czochralski checked later that the crystallised wire was a single crystal. The crystals obtained in that way had diameters of about a millimetre and lengths up to 150 mm. Czochralski published a paper on the study of the rate of crystallisation of tin, zinc and lead, and the maximum rate of pulling of a crystal was recognised as the characteristics of the crystallising material ("Ein neues Verfahren zur Messung des Kristallisationsgeschwindigkeit der Metalle" ["A new method for the measurement of crystallisation rate of metals"], Z. phys. Chem. 92, 219-221 (1918); the paper was received in the editorial office on 19 August 1916). Details of the new method, but without any figure, appeared earlier in another paper published by Czochralski: Zeitschrift des Vereines Deutscher Ingenieure 61, 345-351 (1917)). He is also the author of the first attempt at creating a microscopic theory of recrystallization (Int. Zeitschrift fuer Metallographie 8, 1-43 (116)). The application of the Czochralski method exclusively as a technique for obtaining single crystals is due to W. von Wartenberg (Verhandlungen der Deutsche Phys. Gesellschaft 20, 113 (1918)). Thus, the Czochralski method was a method of producing large single crystals by inserting a small seed crystal into a crucible filled with molten material, then slowly pulling the seed up from the melt with its simultaneous rotation. Later modifications of this method have also been reported. The increasing demand for semiconductor electronic materials led the Americans G.K. Teal and J.B. Little from Bell Telephone Laboratories in Murray Hill, NY, to extend the Czochralski method to the growing of nonmetalic materials, starting with germanium in 1948 (Growth of germanium single crystals, Phys. Rev. 78, 647 (1950)) and soon thereafter silicon. Teal's improvements gave this growth method a world-wide fame as the Czochralski method for growing large single crystals on an industrial scale. At the present, no other crystal growth method can compete with the Czochralski method.
IN FRANKFURT ON MAIN
In 1917 Jan Czochralski moved to Frankfurt on Main and, combining scientific research with workshop efforts, organized the Laboratory of Metal Science of the Metallgesellschaft AG. Several valuable scientific papers and patents were developed there. Among the patents was the highly famous patent on a tin-free bearing alloy for railways, called metal B, patented in 1924 and bought by many countries all over the world, including USA, France and England. He also pioneered investigations of the anisotropy of the hardness of single crystals (works between 1913 and 1923), which are of great importance for the plastic treatment of materials. Czochralski wrote two handbooks: "Lagermetale und ihre technologische Bewertung ["Bearing metal and its technological evaluation"] (coauthored with G. Welter, 1920, 1924) and "Moderne Metallkunde in Theorie and Praxis" ["Modern metal science in theory and practice"] (1924), which were later translated into several languages. Many of Czochralski's works were military secrets (later even in Poland) and have never been published. It is known, however, that during this Frankfurt period he authored reports containing more than two thousand pages. In 1919 Jan Czochralski with a few friends founded German Society for Metals Science (Deutsche Gesellschaft für Metallkunde), and in 1925 became its president. He was also an honorary member of the Institute of Metals in London.
IN POLAND AGAIN
Poland revived after the First World War and required knowledge and capabilities of its sons and daughters scattered all over the world. Jan Czochralski did not forget about his native land despite his high position in the German industry. He returned to Poland at the invitation of the President of Poland, Ignacy Moscicki, an eminent professor of chemistry, and in 1929 he took the position of a professor in the Faculty of Chemistry at the Warsaw University of Technology, where he also obtained the honorary doctorate. He invested the fortune he brought from Germany in Polish industry and arts (i.e. founded artistic scholarships). The drawing rooms of his home became popular in Warsaw. Once again he organised his scientific workshop: Department of Metallurgy and Metals Science in the Warsaw University of Technology and Institute of Metallurgy and Metal Science. The latter mainly worked for the Ministry of Defence. Both of these scientific institutions were equipped with the latest apparatus. Prof. Czochralski also organized Metallurgical Section in the Chemical Research Institute, one of the leading independent research institutions in the country. In the institutions mentioned above, Prof. Czochralski continued the studies, which he undertook earlier in Germany. He was still engaged in measurements of the rate of crystallisation of metals. He also studied the elastic properties of metals and alloys and their corrosion in different gas atmospheres. In addition, Czochralski investigated the influence of experimental conditions on the shape of crystals obtained by his growth method ("Wiadomosci Instytutu Metalurgii i Metaloznawstwa" 3, 69-74 (136); 85-88 (1937)) and studied another method of obtaining single crystals, by recrystallization of initial material. The list of publications by J. Czochralski contains about one hundred papers. A complete list of these papers may be found in Wiadomoci Chemiczne 41, 597 (1987) or in his biography by P. Tomaszewski ("Jan Czochralski and his method", Wroclaw-Kcynia 2003). He was very interested in everything that concerned his native surroundings. He supported both archeological studies as well as the geological search for petroleum beds. He was also interested in the progress of Polish economy and there are even some papers retained from that period.
THE TRAGEDY OF WAR
In the winter of 1939 at the beginning of the II World War, Jan Czochralski Czochralski organized the Department of Materials Research as a service institution. This was at the request of his co-workers from the Warsaw University of Technology closed by Germans. At the price of producing spare parts for the Germans and the city self-government administration, the service institution provided jobs and security (giving appropriate documents) to dozen of persons in occupied Warsaw. It also supplied the Underground National Army fighting for the freedom of the country. Co-operation with the Underground National Army (for example, extracting persons imprisoned by the Germans, helping the Jewish ghetto in Warsaw, saving collections from destroyed museums, and rendering help to Polish men of letters and artists) was the natural feature of the activities of Czochralski. He considered it his moral duty to use his German connections and a good knowledge of the German language for the Polish cause, risking both being imprisoned by the Germans and/or being suspected of collaboration.
RETURN TO KCYNIA
After the war Professor Czochralski decided to return to native Kcynia. With his family he founded there a drug company, BION, producing different types of cosmetics and household chemicals. In this way the circle closed. Jan Czochralski returned to Kcynia and to the chemistry of drugs and pharmacy. On April 22, 1953 he died of heart disease and was buried in Kcynia.
On basis of: P. Tomaszewski "Jan Czochralski and His Method" ed. ATUT and INTiBS PAN, Wroclaw-Kcynia 2003 (ISBN 83-906218-2-7 and ISBN 83-89247-27-5).