- 1916 - Patterson Screen Company Founded by Carl Patterson
- 1936 - First lighting phosphors produced (produced until 2013)
- 1941 - Sylvania Hygrade purchases Patterson Screen Company, manufacturing moved to current location in Towanda
- 1942 - Sodium tungstate produced, a raw material for fluorescent powders.
- 1943 - Tungsten powder produced for the US Government
- 1945 - Tungsten wire produced, marking entry into a major new product line (produced until 2012)
- 1948 - Television phosphors produced (manufactured until 2000)
- 1959 - Sylvania merged with General Telephone, becoming General Telephone & Electronics (GTE)
- 1962 - All the divisions operations are combined in a single site
- 1965 - Aperature masks manufactured for color televisions (a major product line until 1982)
- 1971 - Tungsten metal powder production begins at HMZ in Brúntal Czech Republic
- 1978 - Major period of expansion begins including new and updated manufacturing for phosphor, wire, ready-to-press powders, and thermal spray powders
- 1990 - Tungsten scrap processing begins at HMZ
- 1993 - Siemens purchases Sylvania from GTE
- 2000 - Siemens purchases HMZ
- 2006 - Roaster built for reclaim of soft scrap
- 2008 - Plansee purchases GTP (Towanda and Brúntal) from Siemens
- 2010 - New product line opened - interconnect plates for SOFC
- 2011 - GTP Tungsten Powder Recycling India operation opens
- 2012 - APT capacity expansion
- 2013 - Tungsten production upgrades and improvements begin
- 2015 - GTP acquires Tikomet Oy
