article_snippet: Researchers from Yale University discovered at at least 33 of these (shown) are used for circuit boards.
article_snippet: The team's results show that the limitations for many important metals used in smartphones and other gadgets are largely those related to supply risk.
article_snippet: These include gallium used in processor chips and selenium in transistors on these chips.
article_snippet: While steel alloying elements, such as chromium and niobium, as well as elements used in high-temperature alloys including tungsten and molybdenum, scored higher in the vulnerability to supply restriction category. '
article_snippet: The results  show that  many important metals used in gadgets are largely related to supply risk (A).
article_snippet: These include gallium and selenium.
article_snippet: Chromium, niobium, tungsten and molybdenum scored higher for the vulnerability to supply restriction (C) '
article_snippet: We've been using Chromium, niobium, tungsten and molybdenum for a long time because Chromium, niobium, tungsten and molybdenum're pretty abundant and Chromium, niobium, tungsten and molybdenum are generally widespread geographically. '
article_snippet: There is no substitute for indium, in particular, and this could impact our touchscreens.
highlights_snippet: Paper found that supplies of gallium, arsenic and selenium are high-risk .
  
highlights_snippet: supplies of gallium, arsenic and selenium are high-risk are needed for circuit boards, batteries and more .